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serenity/Userland/Shell/Parser.cpp
Lucas CHOLLET 3f35ffb648 Userland: Prefer _string over _short_string 
As `_string` can't fail anymore (since 3434412), there are no real
benefits to use the short variant in most cases.
2023-08-08 07:37:21 +02:00

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/*
* Copyright (c) 2020-2021, the SerenityOS developers.
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include "Parser.h"
#include "Shell.h"
#include <AK/AllOf.h>
#include <AK/GenericLexer.h>
#include <AK/ScopeGuard.h>
#include <AK/ScopedValueRollback.h>
#include <AK/TemporaryChange.h>
#include <ctype.h>
#include <stdio.h>
#include <unistd.h>
#define TRY_OR_THROW_PARSE_ERROR(expr) ({ \
/* Ignore -Wshadow to allow nesting the macro. */ \
AK_IGNORE_DIAGNOSTIC("-Wshadow", \
auto&& _value_or_error = expr;) \
if (_value_or_error.is_error()) { \
AK_IGNORE_DIAGNOSTIC("-Wshadow", \
auto _error = _value_or_error.release_error();) \
if (_error.is_errno() && _error.code() == ENOMEM) \
return create<AST::SyntaxError>("OOM"_string); \
return create<AST::SyntaxError>(MUST(String::formatted("Error: {}", _error))); \
} \
_value_or_error.release_value(); \
})
#define TRY_OR_RESOLVE_TO_ERROR_STRING(expr) ({ \
/* Ignore -Wshadow to allow nesting the macro. */ \
AK_IGNORE_DIAGNOSTIC("-Wshadow", \
auto&& _value_or_error = expr; \
String _string_value;) \
if (_value_or_error.is_error()) { \
AK_IGNORE_DIAGNOSTIC("-Wshadow", \
auto _error = _value_or_error.release_error();) \
if (_error.is_errno() && _error.code() == ENOMEM) \
_string_value = "OOM"_string; \
else \
_string_value = MUST(String::formatted("Error: {}", _error)); \
} \
_value_or_error.is_error() ? _string_value : _value_or_error.release_value(); \
})
#define TRY_OR(expr, catch_expr) ({ \
/* Ignore -Wshadow to allow nesting the macro. */ \
AK_IGNORE_DIAGNOSTIC("-Wshadow", \
auto&& _value_or_error = expr;) \
if (_value_or_error.is_error()) { \
AK_IGNORE_DIAGNOSTIC("-Wshadow", \
auto _error = _value_or_error.release_error();) \
catch_expr; \
} \
_value_or_error.release_value(); \
})
namespace Shell {
Parser::SavedOffset Parser::save_offset() const
{
return { m_offset, m_line };
}
char Parser::peek()
{
if (at_end())
return 0;
VERIFY(m_offset < m_input.length());
auto ch = m_input[m_offset];
if (ch == '\\' && m_input.length() > m_offset + 1 && m_input[m_offset + 1] == '\n') {
m_offset += 2;
++m_line.line_number;
m_line.line_column = 0;
return peek();
}
return ch;
}
char Parser::consume()
{
if (at_end())
return 0;
auto ch = peek();
++m_offset;
if (ch == '\n') {
++m_line.line_number;
m_line.line_column = 0;
} else {
++m_line.line_column;
}
return ch;
}
bool Parser::expect(char ch)
{
return expect(StringView { &ch, 1 });
}
bool Parser::expect(StringView expected)
{
auto offset_at_start = m_offset;
auto line_at_start = line();
if (expected.length() + m_offset > m_input.length())
return false;
for (auto& c : expected) {
if (peek() != c) {
restore_to(offset_at_start, line_at_start);
return false;
}
consume();
}
return true;
}
template<typename A, typename... Args>
NonnullRefPtr<A> Parser::create(Args&&... args)
{
return adopt_ref(*new A(AST::Position { m_rule_start_offsets.last(), m_offset, m_rule_start_lines.last(), line() }, forward<Args>(args)...));
}
[[nodiscard]] OwnPtr<Parser::ScopedOffset> Parser::push_start()
{
return make<ScopedOffset>(m_rule_start_offsets, m_rule_start_lines, m_offset, m_line.line_number, m_line.line_column);
}
Parser::Offset Parser::current_position()
{
return Offset { m_offset, { m_line.line_number, m_line.line_column } };
}
static constexpr bool is_whitespace(char c)
{
return c == ' ' || c == '\t';
}
static constexpr bool is_digit(char c)
{
return c <= '9' && c >= '0';
}
static constexpr auto is_not(char c)
{
return [c](char ch) { return ch != c; };
}
static inline char to_byte(char a, char b)
{
char buf[3] { a, b, 0 };
return strtol(buf, nullptr, 16);
}
RefPtr<AST::Node> Parser::parse()
{
m_offset = 0;
m_line = { 0, 0 };
auto toplevel = parse_toplevel();
if (m_offset < m_input.length()) {
// Parsing stopped midway, this is a syntax error.
auto error_start = push_start();
while (!at_end())
consume();
auto syntax_error_node = create<AST::SyntaxError>("Unexpected tokens past the end"_string);
if (!toplevel)
toplevel = move(syntax_error_node);
else if (!toplevel->is_syntax_error())
toplevel->set_is_syntax_error(*syntax_error_node);
}
return toplevel;
}
RefPtr<AST::Node> Parser::parse_as_single_expression()
{
auto input = Shell::escape_token_for_double_quotes(m_input);
Parser parser { input };
return parser.parse_expression();
}
Vector<NonnullRefPtr<AST::Node>> Parser::parse_as_multiple_expressions()
{
Vector<NonnullRefPtr<AST::Node>> nodes;
for (;;) {
consume_while(is_whitespace);
auto node = parse_expression();
if (!node)
node = parse_redirection();
if (!node)
return nodes;
nodes.append(node.release_nonnull());
}
}
RefPtr<AST::Node> Parser::parse_toplevel()
{
auto rule_start = push_start();
SequenceParseResult result;
Vector<NonnullRefPtr<AST::Node>> sequence;
Vector<AST::Position> positions;
do {
result = parse_sequence();
if (result.entries.is_empty())
break;
sequence.extend(move(result.entries));
positions.extend(move(result.separator_positions));
} while (result.decision == ShouldReadMoreSequences::Yes);
if (sequence.is_empty())
return nullptr;
return create<AST::Execute>(
create<AST::Sequence>(move(sequence), move(positions)));
}
Parser::SequenceParseResult Parser::parse_sequence()
{
Vector<NonnullRefPtr<AST::Node>> left;
auto read_terminators = [&](bool consider_tabs_and_spaces) {
if (m_heredoc_initiations.is_empty()) {
discard_terminators:;
consume_while(is_any_of(consider_tabs_and_spaces ? " \t\n;"sv : "\n;"sv));
} else {
for (;;) {
if (consider_tabs_and_spaces && (peek() == '\t' || peek() == ' ')) {
consume();
continue;
}
if (peek() == ';') {
consume();
continue;
}
if (peek() == '\n') {
auto rule_start = push_start();
consume();
if (!parse_heredoc_entries()) {
StringBuilder error_builder;
error_builder.append("Expected to find heredoc entries for "sv);
bool first = true;
for (auto& entry : m_heredoc_initiations) {
if (first)
error_builder.appendff("{} (at {}:{})", entry.end, entry.node->position().start_line.line_column, entry.node->position().start_line.line_number);
else
error_builder.appendff(", {} (at {}:{})", entry.end, entry.node->position().start_line.line_column, entry.node->position().start_line.line_number);
first = false;
}
left.append(create<AST::SyntaxError>(TRY_OR_RESOLVE_TO_ERROR_STRING(error_builder.to_string()), true));
// Just read the rest of the newlines
goto discard_terminators;
}
continue;
}
break;
}
}
};
read_terminators(true);
auto rule_start = push_start();
{
auto var_decls = parse_variable_decls();
if (var_decls)
left.append(var_decls.release_nonnull());
}
auto pos_before_seps = save_offset();
switch (peek()) {
case '}':
return { move(left), {}, ShouldReadMoreSequences::No };
case '\n':
read_terminators(false);
[[fallthrough]];
case ';': {
if (left.is_empty())
break;
consume_while(is_any_of("\n;"sv));
auto pos_after_seps = save_offset();
AST::Position separator_position { pos_before_seps.offset, pos_after_seps.offset, pos_before_seps.line, pos_after_seps.line };
return { move(left), { move(separator_position) }, ShouldReadMoreSequences::Yes };
}
default:
break;
}
auto first_entry = parse_function_decl();
Vector<AST::Position> separator_positions;
if (!first_entry)
first_entry = parse_or_logical_sequence();
if (!first_entry)
return { move(left), {}, ShouldReadMoreSequences::No };
left.append(first_entry.release_nonnull());
separator_positions.empend(pos_before_seps.offset, pos_before_seps.offset, pos_before_seps.line, pos_before_seps.line);
consume_while(is_whitespace);
pos_before_seps = save_offset();
switch (peek()) {
case '\n':
read_terminators(false);
[[fallthrough]];
case ';': {
consume_while(is_any_of("\n;"sv));
auto pos_after_seps = save_offset();
separator_positions.empend(pos_before_seps.offset, pos_after_seps.offset, pos_before_seps.line, pos_after_seps.line);
return { move(left), move(separator_positions), ShouldReadMoreSequences::Yes };
}
case '&': {
consume();
auto pos_after_seps = save_offset();
auto bg = create<AST::Background>(left.take_last()); // Execute Background
left.append(move(bg));
separator_positions.empend(pos_before_seps.offset, pos_after_seps.offset, pos_before_seps.line, pos_after_seps.line);
return { move(left), move(separator_positions), ShouldReadMoreSequences::Yes };
}
default:
return { move(left), move(separator_positions), ShouldReadMoreSequences::No };
}
}
RefPtr<AST::Node> Parser::parse_variable_decls()
{
auto rule_start = push_start();
consume_while(is_whitespace);
auto pos_before_name = save_offset();
auto var_name = consume_while(is_word_character);
if (var_name.is_empty())
return nullptr;
if (!expect('=')) {
restore_to(pos_before_name.offset, pos_before_name.line);
return nullptr;
}
auto name_expr = create<AST::BarewordLiteral>(TRY_OR_THROW_PARSE_ERROR(String::from_utf8(var_name)));
auto start = push_start();
auto expression = parse_expression();
if (!expression || expression->is_syntax_error()) {
restore_to(*start);
if (peek() == '(') {
consume();
auto command = parse_pipe_sequence();
if (!command)
restore_to(*start);
else if (!expect(')'))
command->set_is_syntax_error(*create<AST::SyntaxError>("Expected a terminating close paren"_string, true));
expression = command;
}
}
if (!expression) {
if (is_whitespace(peek())) {
auto string_start = push_start();
expression = create<AST::StringLiteral>(String {}, AST::StringLiteral::EnclosureType::None);
} else {
restore_to(pos_before_name.offset, pos_before_name.line);
return nullptr;
}
}
Vector<AST::VariableDeclarations::Variable> variables;
variables.append({ move(name_expr), expression.release_nonnull() });
if (consume_while(is_whitespace).is_empty())
return create<AST::VariableDeclarations>(move(variables));
auto rest = parse_variable_decls();
if (!rest)
return create<AST::VariableDeclarations>(move(variables));
VERIFY(rest->is_variable_decls());
auto* rest_decl = static_cast<AST::VariableDeclarations*>(rest.ptr());
variables.extend(rest_decl->variables());
return create<AST::VariableDeclarations>(move(variables));
}
RefPtr<AST::Node> Parser::parse_function_decl()
{
auto rule_start = push_start();
auto restore = [&] {
restore_to(*rule_start);
return nullptr;
};
consume_while(is_whitespace);
auto pos_before_name = save_offset();
auto function_name = consume_while(is_word_character);
auto pos_after_name = save_offset();
if (function_name.is_empty())
return restore();
if (!expect('('))
return restore();
Vector<AST::NameWithPosition> arguments;
for (;;) {
consume_while(is_whitespace);
if (expect(')'))
break;
auto name_offset = m_offset;
auto start_line = line();
auto arg_name = consume_while(is_word_character);
if (arg_name.is_empty()) {
// FIXME: Should this be a syntax error, or just return?
return restore();
}
arguments.append({ TRY_OR_THROW_PARSE_ERROR(String::from_utf8(arg_name)), { name_offset, m_offset, start_line, line() } });
}
consume_while(is_any_of("\n\t "sv));
{
RefPtr<AST::Node> syntax_error;
{
auto obrace_error_start = push_start();
syntax_error = create<AST::SyntaxError>("Expected an open brace '{' to start a function body"_string, true);
}
if (!expect('{')) {
return create<AST::FunctionDeclaration>(
AST::NameWithPosition {
TRY_OR_THROW_PARSE_ERROR(String::from_utf8(function_name)),
{ pos_before_name.offset, pos_after_name.offset, pos_before_name.line, pos_after_name.line } },
move(arguments),
move(syntax_error));
}
}
TemporaryChange controls { m_continuation_controls_allowed, false };
auto body = parse_toplevel();
{
RefPtr<AST::SyntaxError> syntax_error;
{
auto cbrace_error_start = push_start();
syntax_error = create<AST::SyntaxError>("Expected a close brace '}' to end a function body"_string, true);
}
if (!expect('}')) {
if (body)
body->set_is_syntax_error(*syntax_error);
else
body = move(syntax_error);
return create<AST::FunctionDeclaration>(
AST::NameWithPosition {
TRY_OR_THROW_PARSE_ERROR(String::from_utf8(function_name)),
{ pos_before_name.offset, pos_after_name.offset, pos_before_name.line, pos_after_name.line } },
move(arguments),
move(body));
}
}
return create<AST::FunctionDeclaration>(
AST::NameWithPosition {
TRY_OR_THROW_PARSE_ERROR(String::from_utf8(function_name)),
{ pos_before_name.offset, pos_after_name.offset, pos_before_name.line, pos_after_name.line } },
move(arguments),
move(body));
}
RefPtr<AST::Node> Parser::parse_or_logical_sequence()
{
consume_while(is_whitespace);
auto rule_start = push_start();
auto and_sequence = parse_and_logical_sequence();
if (!and_sequence)
return nullptr;
consume_while(is_whitespace);
auto pos_before_or = save_offset();
if (!expect("||"sv))
return and_sequence;
auto pos_after_or = save_offset();
auto right_and_sequence = parse_and_logical_sequence();
if (!right_and_sequence)
right_and_sequence = create<AST::SyntaxError>("Expected an expression after '||'"_string, true);
return create<AST::Or>(
and_sequence.release_nonnull(),
right_and_sequence.release_nonnull(),
AST::Position { pos_before_or.offset, pos_after_or.offset, pos_before_or.line, pos_after_or.line });
}
RefPtr<AST::Node> Parser::parse_and_logical_sequence()
{
consume_while(is_whitespace);
auto rule_start = push_start();
auto pipe_sequence = parse_pipe_sequence();
if (!pipe_sequence)
return nullptr;
consume_while(is_whitespace);
auto pos_before_and = save_offset();
if (!expect("&&"sv))
return pipe_sequence;
auto pos_after_end = save_offset();
auto right_and_sequence = parse_and_logical_sequence();
if (!right_and_sequence)
right_and_sequence = create<AST::SyntaxError>("Expected an expression after '&&'"_string, true);
return create<AST::And>(
pipe_sequence.release_nonnull(),
right_and_sequence.release_nonnull(),
AST::Position { pos_before_and.offset, pos_after_end.offset, pos_before_and.line, pos_after_end.line });
}
RefPtr<AST::Node> Parser::parse_pipe_sequence()
{
auto rule_start = push_start();
auto left = parse_control_structure();
if (!left) {
if (auto cmd = parse_command())
left = cmd;
else
return nullptr;
}
consume_while(is_whitespace);
if (peek() != '|')
return left;
auto before_pipe = save_offset();
consume();
auto also_pipe_stderr = peek() == '&';
if (also_pipe_stderr) {
consume();
RefPtr<AST::Node> redirection;
{
auto redirection_start = push_start();
redirection = create<AST::Fd2FdRedirection>(STDERR_FILENO, STDOUT_FILENO);
}
left = create<AST::Join>(left.release_nonnull(), redirection.release_nonnull());
}
if (auto pipe_seq = parse_pipe_sequence()) {
return create<AST::Pipe>(left.release_nonnull(), pipe_seq.release_nonnull()); // Pipe
}
restore_to(before_pipe.offset, before_pipe.line);
return left;
}
RefPtr<AST::Node> Parser::parse_command()
{
auto rule_start = push_start();
consume_while(is_whitespace);
auto redir = parse_redirection();
if (!redir) {
auto list_expr = parse_list_expression();
if (!list_expr)
return nullptr;
auto cast = create<AST::CastToCommand>(list_expr.release_nonnull()); // Cast List Command
auto next_command = parse_command();
if (!next_command)
return cast;
return create<AST::Join>(move(cast), next_command.release_nonnull()); // Join List Command
}
auto command = parse_command();
if (!command)
return redir;
return create<AST::Join>(redir.release_nonnull(), command.release_nonnull()); // Join Command Command
}
RefPtr<AST::Node> Parser::parse_control_structure()
{
auto rule_start = push_start();
consume_while(is_whitespace);
if (auto control = parse_continuation_control())
return control;
if (auto for_loop = parse_for_loop())
return for_loop;
if (auto loop = parse_loop_loop())
return loop;
if (auto if_expr = parse_if_expr())
return if_expr;
if (auto subshell = parse_subshell())
return subshell;
if (auto match = parse_match_expr())
return match;
return nullptr;
}
RefPtr<AST::Node> Parser::parse_continuation_control()
{
if (!m_continuation_controls_allowed)
return nullptr;
auto rule_start = push_start();
if (expect("break"sv)) {
{
auto break_end = push_start();
if (consume_while(is_any_of(" \t\n;"sv)).is_empty()) {
restore_to(*rule_start);
return nullptr;
}
restore_to(*break_end);
}
return create<AST::ContinuationControl>(AST::ContinuationControl::Break);
}
if (expect("continue"sv)) {
{
auto continue_end = push_start();
if (consume_while(is_any_of(" \t\n;"sv)).is_empty()) {
restore_to(*rule_start);
return nullptr;
}
restore_to(*continue_end);
}
return create<AST::ContinuationControl>(AST::ContinuationControl::Continue);
}
return nullptr;
}
RefPtr<AST::Node> Parser::parse_for_loop()
{
auto rule_start = push_start();
if (!expect("for"sv))
return nullptr;
if (consume_while(is_any_of(" \t\n"sv)).is_empty()) {
restore_to(*rule_start);
return nullptr;
}
Optional<AST::NameWithPosition> index_variable_name, variable_name;
Optional<AST::Position> in_start_position, index_start_position;
auto offset_before_index = current_position();
if (expect("index"sv)) {
auto offset = current_position();
if (!consume_while(is_whitespace).is_empty()) {
auto offset_before_variable = current_position();
auto variable = consume_while(is_word_character);
if (!variable.is_empty()) {
index_start_position = AST::Position { offset_before_index.offset, offset.offset, offset_before_index.line, offset.line };
auto offset_after_variable = current_position();
index_variable_name = AST::NameWithPosition {
TRY_OR_THROW_PARSE_ERROR(String::from_utf8(variable)),
{ offset_before_variable.offset, offset_after_variable.offset, offset_before_variable.line, offset_after_variable.line },
};
consume_while(is_whitespace);
} else {
restore_to(offset_before_index.offset, offset_before_index.line);
}
} else {
restore_to(offset_before_index.offset, offset_before_index.line);
}
}
auto variable_name_start_offset = current_position();
auto name = consume_while(is_word_character);
auto variable_name_end_offset = current_position();
if (!name.is_empty()) {
variable_name = AST::NameWithPosition {
TRY_OR_THROW_PARSE_ERROR(String::from_utf8(name)),
{ variable_name_start_offset.offset, variable_name_end_offset.offset, variable_name_start_offset.line, variable_name_end_offset.line }
};
consume_while(is_whitespace);
auto in_error_start = push_start();
if (!expect("in"sv)) {
auto syntax_error = create<AST::SyntaxError>("Expected 'in' after a variable name in a 'for' loop"_string, true);
return create<AST::ForLoop>(move(variable_name), move(index_variable_name), move(syntax_error), nullptr); // ForLoop Var Iterated Block
}
in_start_position = AST::Position { in_error_start->offset, m_offset, in_error_start->line, line() };
}
consume_while(is_whitespace);
RefPtr<AST::Node> iterated_expression;
{
auto iter_error_start = push_start();
iterated_expression = parse_expression();
if (!iterated_expression)
iterated_expression = create<AST::SyntaxError>("Expected an expression in 'for' loop"_string, true);
}
consume_while(is_any_of(" \t\n"sv));
{
auto obrace_error_start = push_start();
if (!expect('{')) {
auto syntax_error = create<AST::SyntaxError>("Expected an open brace '{' to start a 'for' loop body"_string, true);
return create<AST::ForLoop>(move(variable_name), move(index_variable_name), move(iterated_expression), move(syntax_error), move(in_start_position), move(index_start_position)); // ForLoop Var Iterated Block
}
}
TemporaryChange controls { m_continuation_controls_allowed, true };
auto body = parse_toplevel();
{
auto cbrace_error_start = push_start();
if (!expect('}')) {
auto error_start = push_start();
auto syntax_error = create<AST::SyntaxError>("Expected a close brace '}' to end a 'for' loop body"_string, true);
if (body)
body->set_is_syntax_error(*syntax_error);
else
body = syntax_error;
}
}
return create<AST::ForLoop>(move(variable_name), move(index_variable_name), move(iterated_expression), move(body), move(in_start_position), move(index_start_position)); // ForLoop Var Iterated Block
}
RefPtr<AST::Node> Parser::parse_loop_loop()
{
auto rule_start = push_start();
if (!expect("loop"sv))
return nullptr;
if (consume_while(is_any_of(" \t\n"sv)).is_empty()) {
restore_to(*rule_start);
return nullptr;
}
{
auto obrace_error_start = push_start();
if (!expect('{')) {
auto syntax_error = create<AST::SyntaxError>("Expected an open brace '{' to start a 'loop' loop body"_string, true);
return create<AST::ForLoop>(AST::NameWithPosition {}, AST::NameWithPosition {}, nullptr, move(syntax_error)); // ForLoop null null Block
}
}
TemporaryChange controls { m_continuation_controls_allowed, true };
auto body = parse_toplevel();
{
auto cbrace_error_start = push_start();
if (!expect('}')) {
auto error_start = push_start();
auto syntax_error = create<AST::SyntaxError>("Expected a close brace '}' to end a 'loop' loop body"_string, true);
if (body)
body->set_is_syntax_error(*syntax_error);
else
body = syntax_error;
}
}
return create<AST::ForLoop>(AST::NameWithPosition {}, AST::NameWithPosition {}, nullptr, move(body)); // ForLoop null null Block
}
RefPtr<AST::Node> Parser::parse_if_expr()
{
auto rule_start = push_start();
if (!expect("if"sv))
return nullptr;
if (consume_while(is_any_of(" \t\n"sv)).is_empty()) {
restore_to(*rule_start);
return nullptr;
}
RefPtr<AST::Node> condition;
{
auto cond_error_start = push_start();
condition = parse_or_logical_sequence();
if (!condition)
condition = create<AST::SyntaxError>("Expected a logical sequence after 'if'"_string, true);
}
auto parse_braced_toplevel = [&]() -> RefPtr<AST::Node> {
RefPtr<AST::Node> body;
{
auto obrace_error_start = push_start();
if (!expect('{')) {
body = create<AST::SyntaxError>("Expected an open brace '{' to start an 'if' true branch"_string, true);
}
}
if (!body)
body = parse_toplevel();
{
auto cbrace_error_start = push_start();
if (!expect('}')) {
auto error_start = push_start();
RefPtr<AST::SyntaxError> syntax_error = create<AST::SyntaxError>("Expected a close brace '}' to end an 'if' true branch"_string, true);
if (body)
body->set_is_syntax_error(*syntax_error);
else
body = syntax_error;
}
}
return body;
};
consume_while(is_any_of(" \t\n"sv));
auto true_branch = parse_braced_toplevel();
auto end_before_else = m_offset;
auto line_before_else = line();
consume_while(is_any_of(" \t\n"sv));
Optional<AST::Position> else_position;
{
auto else_start = push_start();
if (expect("else"sv))
else_position = AST::Position { else_start->offset, m_offset, else_start->line, line() };
else
restore_to(end_before_else, line_before_else);
}
if (else_position.has_value()) {
consume_while(is_any_of(" \t\n"sv));
if (peek() == '{') {
auto false_branch = parse_braced_toplevel();
return create<AST::IfCond>(else_position, condition.release_nonnull(), move(true_branch), move(false_branch)); // If expr true_branch Else false_branch
}
auto else_if_branch = parse_if_expr();
return create<AST::IfCond>(else_position, condition.release_nonnull(), move(true_branch), move(else_if_branch)); // If expr true_branch Else If ...
}
return create<AST::IfCond>(else_position, condition.release_nonnull(), move(true_branch), nullptr); // If expr true_branch
}
RefPtr<AST::Node> Parser::parse_subshell()
{
auto rule_start = push_start();
if (!expect('{'))
return nullptr;
auto body = parse_toplevel();
{
auto cbrace_error_start = push_start();
if (!expect('}')) {
auto error_start = push_start();
RefPtr<AST::SyntaxError> syntax_error = create<AST::SyntaxError>("Expected a close brace '}' to end a subshell"_string, true);
if (body)
body->set_is_syntax_error(*syntax_error);
else
body = syntax_error;
}
}
return create<AST::Subshell>(move(body));
}
RefPtr<AST::Node> Parser::parse_match_expr()
{
auto rule_start = push_start();
if (!expect("match"sv))
return nullptr;
if (consume_while(is_whitespace).is_empty()) {
restore_to(*rule_start);
return nullptr;
}
auto match_expression = parse_expression();
if (!match_expression) {
return create<AST::MatchExpr>(
create<AST::SyntaxError>("Expected an expression after 'match'"_string, true),
String {}, Optional<AST::Position> {}, Vector<AST::MatchEntry> {});
}
consume_while(is_any_of(" \t\n"sv));
String match_name;
Optional<AST::Position> as_position;
auto as_start = m_offset;
auto as_line = line();
if (expect("as"sv)) {
as_position = AST::Position { as_start, m_offset, as_line, line() };
if (consume_while(is_any_of(" \t\n"sv)).is_empty()) {
auto node = create<AST::MatchExpr>(
match_expression.release_nonnull(),
String {}, move(as_position), Vector<AST::MatchEntry> {});
node->set_is_syntax_error(create<AST::SyntaxError>("Expected whitespace after 'as' in 'match'"_string, true));
return node;
}
match_name = TRY_OR_THROW_PARSE_ERROR(String::from_utf8(consume_while(is_word_character)));
if (match_name.is_empty()) {
auto node = create<AST::MatchExpr>(
match_expression.release_nonnull(),
String {}, move(as_position), Vector<AST::MatchEntry> {});
node->set_is_syntax_error(create<AST::SyntaxError>("Expected an identifier after 'as' in 'match'"_string, true));
return node;
}
}
consume_while(is_any_of(" \t\n"sv));
if (!expect('{')) {
auto node = create<AST::MatchExpr>(
match_expression.release_nonnull(),
move(match_name), move(as_position), Vector<AST::MatchEntry> {});
node->set_is_syntax_error(create<AST::SyntaxError>("Expected an open brace '{' to start a 'match' entry list"_string, true));
return node;
}
consume_while(is_any_of(" \t\n"sv));
Vector<AST::MatchEntry> entries;
for (;;) {
auto entry = parse_match_entry();
consume_while(is_any_of(" \t\n"sv));
if (entry.options.visit([](auto& x) { return x.is_empty(); }))
break;
entries.append(move(entry));
}
consume_while(is_any_of(" \t\n"sv));
if (!expect('}')) {
auto node = create<AST::MatchExpr>(
match_expression.release_nonnull(),
move(match_name), move(as_position), move(entries));
node->set_is_syntax_error(create<AST::SyntaxError>("Expected a close brace '}' to end a 'match' entry list"_string, true));
return node;
}
return create<AST::MatchExpr>(match_expression.release_nonnull(), move(match_name), move(as_position), move(entries));
}
AST::MatchEntry Parser::parse_match_entry()
{
auto rule_start = push_start();
Vector<NonnullRefPtr<AST::Node>> patterns;
Vector<Regex<ECMA262>> regexps;
Vector<AST::Position> pipe_positions;
Optional<Vector<String>> match_names;
Optional<AST::Position> match_as_position;
enum {
Regex,
Glob,
} pattern_kind;
consume_while(is_any_of(" \t\n"sv));
auto regex_pattern = parse_regex_pattern();
if (regex_pattern.has_value()) {
if (auto error = regex_pattern.value().parser_result.error; error != regex::Error::NoError)
return { Vector<NonnullRefPtr<AST::Node>> {}, {}, {}, {}, create<AST::SyntaxError>(TRY_OR_RESOLVE_TO_ERROR_STRING(String::from_utf8(regex::get_error_string(error))), false) };
pattern_kind = Regex;
regexps.append(regex_pattern.release_value());
} else {
auto glob_pattern = parse_match_pattern();
if (!glob_pattern)
return { Vector<NonnullRefPtr<AST::Node>> {}, {}, {}, {}, create<AST::SyntaxError>("Expected a pattern in 'match' body"_string, true) };
pattern_kind = Glob;
patterns.append(glob_pattern.release_nonnull());
}
consume_while(is_any_of(" \t\n"sv));
auto previous_pipe_start_position = m_offset;
auto previous_pipe_start_line = line();
RefPtr<AST::SyntaxError> error;
while (expect('|')) {
pipe_positions.append({ previous_pipe_start_position, m_offset, previous_pipe_start_line, line() });
consume_while(is_any_of(" \t\n"sv));
switch (pattern_kind) {
case Regex: {
auto pattern = parse_regex_pattern();
if (!pattern.has_value()) {
error = create<AST::SyntaxError>("Expected a regex pattern to follow '|' in 'match' body"_string, true);
break;
}
regexps.append(pattern.release_value());
break;
}
case Glob: {
auto pattern = parse_match_pattern();
if (!pattern) {
error = create<AST::SyntaxError>("Expected a pattern to follow '|' in 'match' body"_string, true);
break;
}
patterns.append(pattern.release_nonnull());
break;
}
}
consume_while(is_any_of(" \t\n"sv));
previous_pipe_start_line = line();
previous_pipe_start_position = m_offset;
}
consume_while(is_any_of(" \t\n"sv));
auto as_start_position = m_offset;
auto as_start_line = line();
if (pattern_kind == Glob && expect("as"sv)) {
match_as_position = AST::Position { as_start_position, m_offset, as_start_line, line() };
consume_while(is_any_of(" \t\n"sv));
if (!expect('(')) {
if (!error)
error = create<AST::SyntaxError>("Expected an explicit list of identifiers after a pattern 'as'"_string);
} else {
match_names = Vector<String>();
for (;;) {
consume_while(is_whitespace);
auto name = consume_while(is_word_character);
if (name.is_empty())
break;
match_names->append(TRY_OR(
String::from_utf8(name),
error = create<AST::SyntaxError>(MUST(String::from_utf8(_error.string_literal())));
break;));
}
if (!expect(')')) {
if (!error)
error = create<AST::SyntaxError>("Expected a close paren ')' to end the identifier list of pattern 'as'"_string, true);
}
}
consume_while(is_any_of(" \t\n"sv));
}
if (pattern_kind == Regex) {
Vector<String> names;
for (auto& regex : regexps) {
if (names.is_empty()) {
for (auto& name : regex.parser_result.capture_groups)
names.append(TRY_OR(
String::from_deprecated_string(name),
error = create<AST::SyntaxError>(MUST(String::from_utf8(_error.string_literal())));
break;));
} else {
size_t index = 0;
for (auto& name : regex.parser_result.capture_groups) {
if (names.size() <= index) {
names.append(TRY_OR(
String::from_deprecated_string(name),
error = create<AST::SyntaxError>(MUST(String::from_utf8(_error.string_literal())));
break;));
continue;
}
if (names[index] != name.view()) {
if (!error)
error = create<AST::SyntaxError>("Alternative regex patterns must have the same capture groups"_string, false);
break;
}
}
}
}
match_names = move(names);
}
if (!expect('{')) {
if (!error)
error = create<AST::SyntaxError>("Expected an open brace '{' to start a match entry body"_string, true);
}
auto body = parse_toplevel();
if (!expect('}')) {
if (!error)
error = create<AST::SyntaxError>("Expected a close brace '}' to end a match entry body"_string, true);
}
if (body && error)
body->set_is_syntax_error(*error);
else if (error)
body = error;
if (pattern_kind == Glob)
return { move(patterns), move(match_names), move(match_as_position), move(pipe_positions), move(body) };
return { move(regexps), move(match_names), move(match_as_position), move(pipe_positions), move(body) };
}
RefPtr<AST::Node> Parser::parse_match_pattern()
{
return parse_expression();
}
Optional<Regex<ECMA262>> Parser::parse_regex_pattern()
{
auto rule_start = push_start();
auto start = m_offset;
if (!expect("(?:"sv) && !expect("(?<"sv))
return {};
size_t open_parens = 1;
while (open_parens > 0) {
if (at_end())
break;
if (next_is("("sv))
++open_parens;
else if (next_is(")"sv))
--open_parens;
consume();
}
if (open_parens != 0) {
restore_to(*rule_start);
return {};
}
auto end = m_offset;
auto pattern = m_input.substring_view(start, end - start);
return Regex<ECMA262>(pattern);
}
RefPtr<AST::Node> Parser::parse_redirection()
{
auto rule_start = push_start();
// heredoc entry
if (next_is("<<-"sv) || next_is("<<~"sv))
return nullptr;
auto pipe_fd = 0;
auto number = consume_while(is_digit);
if (number.is_empty()) {
pipe_fd = -1;
} else {
auto fd = number.to_int();
pipe_fd = fd.value_or(-1);
}
switch (peek()) {
case '>': {
consume();
if (peek() == '>') {
consume();
consume_while(is_whitespace);
pipe_fd = pipe_fd >= 0 ? pipe_fd : STDOUT_FILENO;
auto path = parse_expression();
if (!path) {
if (!at_end()) {
// Eat a character and hope the problem goes away
consume();
}
path = create<AST::SyntaxError>("Expected a path after redirection"_string, true);
}
return create<AST::WriteAppendRedirection>(pipe_fd, path.release_nonnull()); // Redirection WriteAppend
}
if (peek() == '&') {
consume();
// FIXME: 'fd>&-' Syntax not the best. needs discussion.
if (peek() == '-') {
consume();
pipe_fd = pipe_fd >= 0 ? pipe_fd : STDOUT_FILENO;
return create<AST::CloseFdRedirection>(pipe_fd); // Redirection CloseFd
}
int dest_pipe_fd = 0;
auto number = consume_while(is_digit);
pipe_fd = pipe_fd >= 0 ? pipe_fd : STDOUT_FILENO;
if (number.is_empty()) {
dest_pipe_fd = -1;
} else {
auto fd = number.to_int();
dest_pipe_fd = fd.value_or(-1);
}
auto redir = create<AST::Fd2FdRedirection>(pipe_fd, dest_pipe_fd); // Redirection Fd2Fd
if (dest_pipe_fd == -1)
redir->set_is_syntax_error(*create<AST::SyntaxError>("Expected a file descriptor"_string));
return redir;
}
consume_while(is_whitespace);
pipe_fd = pipe_fd >= 0 ? pipe_fd : STDOUT_FILENO;
auto path = parse_expression();
if (!path) {
if (!at_end()) {
// Eat a character and hope the problem goes away
consume();
}
path = create<AST::SyntaxError>("Expected a path after redirection"_string, true);
}
return create<AST::WriteRedirection>(pipe_fd, path.release_nonnull()); // Redirection Write
}
case '<': {
consume();
enum {
Read,
ReadWrite,
} mode { Read };
if (peek() == '>') {
mode = ReadWrite;
consume();
}
consume_while(is_whitespace);
pipe_fd = pipe_fd >= 0 ? pipe_fd : STDIN_FILENO;
auto path = parse_expression();
if (!path) {
if (!at_end()) {
// Eat a character and hope the problem goes away
consume();
}
path = create<AST::SyntaxError>("Expected a path after redirection"_string, true);
}
if (mode == Read)
return create<AST::ReadRedirection>(pipe_fd, path.release_nonnull()); // Redirection Read
return create<AST::ReadWriteRedirection>(pipe_fd, path.release_nonnull()); // Redirection ReadWrite
}
default:
restore_to(*rule_start);
return nullptr;
}
}
RefPtr<AST::Node> Parser::parse_list_expression()
{
consume_while(is_whitespace);
auto rule_start = push_start();
Vector<NonnullRefPtr<AST::Node>> nodes;
do {
auto expr = parse_expression();
if (!expr)
break;
nodes.append(expr.release_nonnull());
} while (!consume_while(is_whitespace).is_empty());
if (nodes.is_empty())
return nullptr;
return create<AST::ListConcatenate>(move(nodes)); // Concatenate List
}
RefPtr<AST::Node> Parser::parse_expression()
{
auto rule_start = push_start();
if (m_rule_start_offsets.size() > max_allowed_nested_rule_depth)
return create<AST::SyntaxError>(TRY_OR_RESOLVE_TO_ERROR_STRING(String::formatted("Expression nested too deep (max allowed is {})", max_allowed_nested_rule_depth)));
auto starting_char = peek();
auto read_concat = [&](auto&& expr) -> NonnullRefPtr<AST::Node> {
if (is_whitespace(peek()))
return move(expr);
if (auto next_expr = parse_expression())
return create<AST::Juxtaposition>(move(expr), next_expr.release_nonnull());
return move(expr);
};
// Heredocs are expressions, so allow them
if (!(next_is("<<-"sv) || next_is("<<~"sv))) {
if (strchr("&|)} ;<>\n", starting_char) != nullptr)
return nullptr;
}
if (m_extra_chars_not_allowed_in_barewords.contains_slow(starting_char))
return nullptr;
if (m_is_in_brace_expansion_spec && next_is(".."sv))
return nullptr;
if (isdigit(starting_char)) {
ScopedValueRollback offset_rollback { m_offset };
auto redir = parse_redirection();
if (redir)
return nullptr;
}
if (starting_char == '$') {
if (auto variable = parse_variable())
return read_concat(variable.release_nonnull());
if (auto immediate = parse_immediate_expression())
return read_concat(immediate.release_nonnull());
auto inline_exec = parse_evaluate();
if (inline_exec && !inline_exec->is_syntax_error())
return read_concat(inline_exec.release_nonnull());
return inline_exec;
}
if (starting_char == '#')
return parse_comment();
if (starting_char == '(') {
consume();
auto list = parse_list_expression();
if (!expect(')')) {
restore_to(*rule_start);
return nullptr;
}
return read_concat(create<AST::CastToList>(move(list))); // Cast To List
}
if (starting_char == '!' && m_in_interactive_mode) {
if (auto designator = parse_history_designator())
return designator;
}
if (auto composite = parse_string_composite())
return read_concat(composite.release_nonnull());
return nullptr;
}
RefPtr<AST::Node> Parser::parse_string_composite()
{
auto rule_start = push_start();
if (auto string = parse_string()) {
if (auto next_part = parse_string_composite())
return create<AST::Juxtaposition>(string.release_nonnull(), next_part.release_nonnull()); // Concatenate String StringComposite
return string;
}
if (auto variable = parse_variable()) {
if (auto next_part = parse_string_composite())
return create<AST::Juxtaposition>(variable.release_nonnull(), next_part.release_nonnull()); // Concatenate Variable StringComposite
return variable;
}
if (auto glob = parse_glob()) {
if (auto next_part = parse_string_composite())
return create<AST::Juxtaposition>(glob.release_nonnull(), next_part.release_nonnull()); // Concatenate Glob StringComposite
return glob;
}
if (auto expansion = parse_brace_expansion()) {
if (auto next_part = parse_string_composite())
return create<AST::Juxtaposition>(expansion.release_nonnull(), next_part.release_nonnull()); // Concatenate BraceExpansion StringComposite
return expansion;
}
if (auto bareword = parse_bareword()) {
if (auto next_part = parse_string_composite())
return create<AST::Juxtaposition>(bareword.release_nonnull(), next_part.release_nonnull()); // Concatenate Bareword StringComposite
return bareword;
}
if (auto inline_command = parse_evaluate()) {
if (auto next_part = parse_string_composite())
return create<AST::Juxtaposition>(inline_command.release_nonnull(), next_part.release_nonnull()); // Concatenate Execute StringComposite
return inline_command;
}
if (auto heredoc = parse_heredoc_initiation_record()) {
if (auto next_part = parse_string_composite())
return create<AST::Juxtaposition>(heredoc.release_nonnull(), next_part.release_nonnull()); // Concatenate Heredoc StringComposite
return heredoc;
}
return nullptr;
}
RefPtr<AST::Node> Parser::parse_string()
{
auto rule_start = push_start();
if (at_end())
return nullptr;
if (peek() == '"') {
consume();
auto inner = parse_string_inner(StringEndCondition::DoubleQuote);
if (!inner)
inner = create<AST::SyntaxError>("Unexpected EOF in string"_string, true);
if (!expect('"')) {
inner = create<AST::DoubleQuotedString>(move(inner));
inner->set_is_syntax_error(*create<AST::SyntaxError>("Expected a terminating double quote"_string, true));
return inner;
}
return create<AST::DoubleQuotedString>(move(inner)); // Double Quoted String
}
if (peek() == '\'') {
consume();
auto text = consume_while(is_not('\''));
bool is_error = false;
if (!expect('\''))
is_error = true;
auto result = create<AST::StringLiteral>(TRY_OR_THROW_PARSE_ERROR(String::from_utf8(text)), AST::StringLiteral::EnclosureType::SingleQuotes); // String Literal
if (is_error)
result->set_is_syntax_error(*create<AST::SyntaxError>("Expected a terminating single quote"_string, true));
return result;
}
return nullptr;
}
RefPtr<AST::Node> Parser::parse_string_inner(StringEndCondition condition)
{
auto rule_start = push_start();
if (at_end())
return nullptr;
StringBuilder builder;
while (!at_end()) {
if (condition == StringEndCondition::DoubleQuote && peek() == '"') {
break;
}
if (peek() == '\\') {
consume();
if (at_end()) {
break;
}
auto ch = consume();
switch (ch) {
case '\\':
default:
builder.append(ch);
break;
case 'x': {
if (m_input.length() <= m_offset + 2)
break;
auto first_nibble = tolower(consume());
auto second_nibble = tolower(consume());
if (!isxdigit(first_nibble) || !isxdigit(second_nibble)) {
builder.append(first_nibble);
builder.append(second_nibble);
break;
}
builder.append(to_byte(first_nibble, second_nibble));
break;
}
case 'u': {
if (m_input.length() <= m_offset + 8)
break;
size_t counter = 8;
auto chars = consume_while([&](auto) { return counter-- > 0; });
if (auto number = AK::StringUtils::convert_to_uint_from_hex(chars); number.has_value())
builder.append(Utf32View { &number.value(), 1 });
else
builder.append(chars);
break;
}
case 'a':
builder.append('\a');
break;
case 'b':
builder.append('\b');
break;
case 'e':
builder.append('\x1b');
break;
case 'f':
builder.append('\f');
break;
case 'r':
builder.append('\r');
break;
case 'n':
builder.append('\n');
break;
case 't':
builder.append('\t');
break;
}
continue;
}
if (peek() == '$') {
auto string_literal = create<AST::StringLiteral>(TRY_OR_THROW_PARSE_ERROR(builder.to_string()), AST::StringLiteral::EnclosureType::DoubleQuotes); // String Literal
auto read_concat = [&](auto&& node) {
auto inner = create<AST::StringPartCompose>(
move(string_literal),
move(node)); // Compose String Node
if (auto string = parse_string_inner(condition)) {
return create<AST::StringPartCompose>(move(inner), string.release_nonnull()); // Compose Composition Composition
}
return inner;
};
if (auto variable = parse_variable())
return read_concat(variable.release_nonnull());
if (auto immediate = parse_immediate_expression())
return read_concat(immediate.release_nonnull());
if (auto evaluate = parse_evaluate())
return read_concat(evaluate.release_nonnull());
}
builder.append(consume());
}
return create<AST::StringLiteral>(TRY_OR_THROW_PARSE_ERROR(builder.to_string()), AST::StringLiteral::EnclosureType::DoubleQuotes); // String Literal
}
RefPtr<AST::Node> Parser::parse_variable()
{
auto rule_start = push_start();
auto ref = parse_variable_ref();
if (!ref)
return nullptr;
auto variable = static_ptr_cast<AST::VariableNode>(ref);
if (auto slice = parse_slice())
variable->set_slice(slice.release_nonnull());
return variable;
}
RefPtr<AST::Node> Parser::parse_variable_ref()
{
auto rule_start = push_start();
if (at_end())
return nullptr;
if (peek() != '$')
return nullptr;
consume();
switch (peek()) {
case '$':
case '?':
case '*':
case '#':
return create<AST::SpecialVariable>(consume()); // Variable Special
default:
break;
}
auto name = consume_while(is_word_character);
if (name.length() == 0) {
restore_to(rule_start->offset, rule_start->line);
return nullptr;
}
return create<AST::SimpleVariable>(TRY_OR_THROW_PARSE_ERROR(String::from_utf8(name))); // Variable Simple
}
RefPtr<AST::Slice> Parser::parse_slice()
{
auto rule_start = push_start();
if (!next_is("["sv))
return nullptr;
consume(); // [
ScopedValueRollback chars_change { m_extra_chars_not_allowed_in_barewords };
m_extra_chars_not_allowed_in_barewords.append(']');
auto spec = parse_brace_expansion_spec();
RefPtr<AST::SyntaxError> error;
if (peek() != ']')
error = create<AST::SyntaxError>("Expected a close bracket ']' to end a variable slice"_string);
else
consume();
if (!spec) {
if (error)
spec = move(error);
else
spec = create<AST::SyntaxError>("Expected either a range, or a comma-seprated list of selectors"_string);
}
auto node = create<AST::Slice>(spec.release_nonnull());
if (error)
node->set_is_syntax_error(*error);
return node;
}
RefPtr<AST::Node> Parser::parse_evaluate()
{
auto rule_start = push_start();
if (at_end())
return nullptr;
if (peek() != '$')
return nullptr;
consume();
if (peek() == '(') {
consume();
auto inner = parse_pipe_sequence();
if (!inner)
inner = create<AST::SyntaxError>("Unexpected EOF in list"_string, true);
if (!expect(')'))
inner->set_is_syntax_error(*create<AST::SyntaxError>("Expected a terminating close paren"_string, true));
return create<AST::Execute>(inner.release_nonnull(), true);
}
auto inner = parse_expression();
if (!inner) {
inner = create<AST::SyntaxError>("Expected a command"_string, true);
} else {
if (inner->is_list()) {
auto execute_inner = create<AST::Execute>(inner.release_nonnull(), true);
inner = move(execute_inner);
} else {
auto dyn_inner = create<AST::DynamicEvaluate>(inner.release_nonnull());
inner = move(dyn_inner);
}
}
return inner;
}
RefPtr<AST::Node> Parser::parse_immediate_expression()
{
auto rule_start = push_start();
if (at_end())
return nullptr;
if (peek() != '$')
return nullptr;
consume();
if (peek() != '{') {
restore_to(*rule_start);
return nullptr;
}
consume();
consume_while(is_whitespace);
auto function_name_start_offset = current_position();
auto function_name = consume_while(is_word_character);
auto function_name_end_offset = current_position();
AST::Position function_position {
function_name_start_offset.offset,
function_name_end_offset.offset,
function_name_start_offset.line,
function_name_end_offset.line,
};
consume_while(is_whitespace);
Vector<NonnullRefPtr<AST::Node>> arguments;
do {
auto expr = parse_expression();
if (!expr)
break;
arguments.append(expr.release_nonnull());
} while (!consume_while(is_whitespace).is_empty());
auto ending_brace_start_offset = current_position();
if (peek() == '}')
consume();
auto ending_brace_end_offset = current_position();
auto ending_brace_position = ending_brace_start_offset.offset == ending_brace_end_offset.offset
? Optional<AST::Position> {}
: Optional<AST::Position> {
AST::Position {
ending_brace_start_offset.offset,
ending_brace_end_offset.offset,
ending_brace_start_offset.line,
ending_brace_end_offset.line,
}
};
auto node = create<AST::ImmediateExpression>(
AST::NameWithPosition { TRY_OR_THROW_PARSE_ERROR(String::from_utf8(function_name)), move(function_position) },
move(arguments),
ending_brace_position);
if (!ending_brace_position.has_value())
node->set_is_syntax_error(create<AST::SyntaxError>("Expected a closing brace '}' to end an immediate expression"_string, true));
else if (node->function_name().is_empty())
node->set_is_syntax_error(create<AST::SyntaxError>("Expected an immediate function name"_string));
return node;
}
RefPtr<AST::Node> Parser::parse_history_designator()
{
auto rule_start = push_start();
VERIFY(peek() == '!');
consume();
// Event selector
AST::HistorySelector selector;
RefPtr<AST::SyntaxError> syntax_error;
selector.event.kind = AST::HistorySelector::EventKind::StartingStringLookup;
selector.event.text_position = { m_offset, m_offset, m_line, m_line };
selector.word_selector_range = {
AST::HistorySelector::WordSelector {
AST::HistorySelector::WordSelectorKind::Index,
0,
{ m_offset, m_offset, m_line, m_line },
nullptr },
AST::HistorySelector::WordSelector {
AST::HistorySelector::WordSelectorKind::Last,
0,
{ m_offset, m_offset, m_line, m_line },
nullptr }
};
bool is_word_selector = false;
switch (peek()) {
case ':':
consume();
[[fallthrough]];
case '^':
case '$':
case '*':
is_word_selector = true;
break;
case '!':
consume();
selector.event.kind = AST::HistorySelector::EventKind::IndexFromEnd;
selector.event.index = 0;
selector.event.text = "!"_string;
break;
case '?':
consume();
selector.event.kind = AST::HistorySelector::EventKind::ContainingStringLookup;
[[fallthrough]];
default: {
TemporaryChange chars_change { m_extra_chars_not_allowed_in_barewords, { ':', '^', '$', '*' } };
auto bareword = parse_bareword();
if (!bareword || !bareword->is_bareword()) {
restore_to(*rule_start);
return nullptr;
}
selector.event.text = static_ptr_cast<AST::BarewordLiteral>(bareword)->text();
selector.event.text_position = bareword->position();
auto selector_bytes = selector.event.text.bytes();
auto it = selector_bytes.begin();
bool is_negative = false;
if (*it == '-') {
++it;
is_negative = true;
}
if (it != selector_bytes.end() && all_of(it, selector_bytes.end(), is_digit)) {
if (is_negative)
selector.event.kind = AST::HistorySelector::EventKind::IndexFromEnd;
else
selector.event.kind = AST::HistorySelector::EventKind::IndexFromStart;
auto number = abs(selector.event.text.bytes_as_string_view().to_int().value_or(0));
if (number != 0)
selector.event.index = number - 1;
else
syntax_error = create<AST::SyntaxError>("History entry index value invalid or out of range"_string);
}
if (":^$*"sv.contains(peek())) {
is_word_selector = true;
if (peek() == ':')
consume();
}
}
}
if (!is_word_selector) {
auto node = create<AST::HistoryEvent>(move(selector));
if (syntax_error)
node->set_is_syntax_error(*syntax_error);
return node;
}
// Word selectors
auto parse_word_selector = [&]() -> Optional<AST::HistorySelector::WordSelector> {
auto c = peek();
AST::HistorySelector::WordSelectorKind word_selector_kind;
ssize_t offset = -1;
if (isdigit(c)) {
auto num = consume_while(is_digit);
auto value = num.to_uint();
if (!value.has_value())
return {};
word_selector_kind = AST::HistorySelector::WordSelectorKind::Index;
offset = value.value();
} else if (c == '^') {
consume();
word_selector_kind = AST::HistorySelector::WordSelectorKind::Index;
offset = 1;
} else if (c == '$') {
consume();
word_selector_kind = AST::HistorySelector::WordSelectorKind::Last;
offset = 0;
}
if (offset == -1)
return {};
return AST::HistorySelector::WordSelector {
word_selector_kind,
static_cast<size_t>(offset),
{ m_rule_start_offsets.last(), m_offset, m_rule_start_lines.last(), line() },
syntax_error
};
};
auto make_word_selector = [&](AST::HistorySelector::WordSelectorKind word_selector_kind, size_t offset) {
return AST::HistorySelector::WordSelector {
word_selector_kind,
offset,
{ m_rule_start_offsets.last(), m_offset, m_rule_start_lines.last(), line() },
syntax_error
};
};
auto first_char = peek();
if (!(is_digit(first_char) || "^$-*"sv.contains(first_char))) {
if (!syntax_error)
syntax_error = create<AST::SyntaxError>("Expected a word selector after ':' in a history event designator"_string, true);
} else if (first_char == '*') {
consume();
selector.word_selector_range.start = make_word_selector(AST::HistorySelector::WordSelectorKind::Index, 1);
selector.word_selector_range.end = make_word_selector(AST::HistorySelector::WordSelectorKind::Last, 0);
} else if (first_char == '-') {
consume();
selector.word_selector_range.start = make_word_selector(AST::HistorySelector::WordSelectorKind::Index, 0);
auto last_selector = parse_word_selector();
if (!last_selector.has_value())
selector.word_selector_range.end = make_word_selector(AST::HistorySelector::WordSelectorKind::Last, 1);
else
selector.word_selector_range.end = last_selector.release_value();
} else {
auto first_selector = parse_word_selector();
// peek() should be a digit, ^, or $ here, so this should always have value.
VERIFY(first_selector.has_value());
selector.word_selector_range.start = first_selector.release_value();
if (peek() == '-') {
consume();
auto last_selector = parse_word_selector();
if (last_selector.has_value()) {
selector.word_selector_range.end = last_selector.release_value();
} else {
selector.word_selector_range.end = make_word_selector(AST::HistorySelector::WordSelectorKind::Last, 1);
}
} else if (peek() == '*') {
consume();
selector.word_selector_range.end = make_word_selector(AST::HistorySelector::WordSelectorKind::Last, 0);
} else {
selector.word_selector_range.end.clear();
}
}
auto node = create<AST::HistoryEvent>(move(selector));
if (syntax_error)
node->set_is_syntax_error(*syntax_error);
return node;
}
RefPtr<AST::Node> Parser::parse_comment()
{
if (at_end())
return nullptr;
if (peek() != '#')
return nullptr;
consume();
auto text = consume_while(is_not('\n'));
return create<AST::Comment>(TRY_OR_THROW_PARSE_ERROR(String::from_utf8(text))); // Comment
}
RefPtr<AST::Node> Parser::parse_bareword()
{
auto rule_start = push_start();
StringBuilder builder;
auto is_acceptable_bareword_character = [&](char c) {
return strchr("\\\"'*$&#|(){} ?;<>\n", c) == nullptr
&& !m_extra_chars_not_allowed_in_barewords.contains_slow(c);
};
while (!at_end()) {
char ch = peek();
if (ch == '\\') {
consume();
if (!at_end()) {
ch = consume();
if (is_acceptable_bareword_character(ch))
builder.append('\\');
}
builder.append(ch);
continue;
}
if (m_is_in_brace_expansion_spec && next_is(".."sv)) {
// Don't eat '..' in a brace expansion spec.
break;
}
if (is_acceptable_bareword_character(ch)) {
builder.append(consume());
continue;
}
break;
}
if (builder.is_empty())
return nullptr;
auto current_end = m_offset;
auto current_line = line();
auto string = TRY_OR_THROW_PARSE_ERROR(builder.to_string());
if (string.starts_with('~')) {
String username;
RefPtr<AST::Node> tilde, text;
auto first_slash_index = string.find_byte_offset('/');
if (first_slash_index.has_value()) {
username = TRY_OR_THROW_PARSE_ERROR(string.substring_from_byte_offset(1, *first_slash_index - 1));
string = TRY_OR_THROW_PARSE_ERROR(string.substring_from_byte_offset(*first_slash_index));
} else {
username = TRY_OR_THROW_PARSE_ERROR(string.substring_from_byte_offset(1));
string = {};
}
// Synthesize a Tilde Node with the correct positioning information.
{
restore_to(rule_start->offset, rule_start->line);
auto ch = consume();
VERIFY(ch == '~');
auto username_length = username.bytes_as_string_view().length();
tilde = create<AST::Tilde>(move(username));
// Consume the username (if any)
for (size_t i = 0; i < username_length; ++i)
consume();
}
if (string.is_empty())
return tilde;
// Synthesize a BarewordLiteral Node with the correct positioning information.
{
auto text_start = push_start();
restore_to(current_end, current_line);
text = create<AST::BarewordLiteral>(move(string));
}
return create<AST::Juxtaposition>(tilde.release_nonnull(), text.release_nonnull()); // Juxtaposition Variable Bareword
}
if (string.starts_with_bytes("\\~"sv)) {
// Un-escape the tilde, but only at the start (where it would be an expansion)
string = TRY_OR_THROW_PARSE_ERROR(string.substring_from_byte_offset(1));
}
return create<AST::BarewordLiteral>(move(string)); // Bareword Literal
}
RefPtr<AST::Node> Parser::parse_glob()
{
auto rule_start = push_start();
auto bareword_part = parse_bareword();
if (at_end())
return bareword_part;
char ch = peek();
if (ch == '*' || ch == '?') {
auto saved_offset = save_offset();
consume();
StringBuilder textbuilder;
if (bareword_part) {
StringView text;
if (bareword_part->is_bareword()) {
auto bareword = static_cast<AST::BarewordLiteral*>(bareword_part.ptr());
text = bareword->text();
} else {
// FIXME: Allow composition of tilde+bareword with globs: '~/foo/bar/baz*'
restore_to(saved_offset.offset, saved_offset.line);
bareword_part->set_is_syntax_error(*create<AST::SyntaxError>(TRY_OR_RESOLVE_TO_ERROR_STRING(String::formatted("Unexpected {} inside a glob", bareword_part->class_name()))));
return bareword_part;
}
textbuilder.append(text);
}
textbuilder.append(ch);
auto glob_after = parse_glob();
if (glob_after) {
if (glob_after->is_glob()) {
auto glob = static_cast<AST::Glob*>(glob_after.ptr());
textbuilder.append(glob->text());
} else if (glob_after->is_bareword()) {
auto bareword = static_cast<AST::BarewordLiteral*>(glob_after.ptr());
textbuilder.append(bareword->text());
} else if (glob_after->is_tilde()) {
auto bareword = static_cast<AST::Tilde*>(glob_after.ptr());
textbuilder.append('~');
textbuilder.append(bareword->text());
} else {
return create<AST::SyntaxError>(TRY_OR_RESOLVE_TO_ERROR_STRING(String::formatted("Invalid node '{}' in glob position, escape shell special characters", glob_after->class_name())));
}
}
return create<AST::Glob>(TRY_OR_THROW_PARSE_ERROR(textbuilder.to_string())); // Glob
}
return bareword_part;
}
RefPtr<AST::Node> Parser::parse_brace_expansion()
{
auto rule_start = push_start();
if (!expect('{'))
return nullptr;
if (auto spec = parse_brace_expansion_spec()) {
if (!expect('}'))
spec->set_is_syntax_error(create<AST::SyntaxError>("Expected a close brace '}' to end a brace expansion"_string, true));
return spec;
}
restore_to(*rule_start);
return nullptr;
}
RefPtr<AST::Node> Parser::parse_brace_expansion_spec()
{
TemporaryChange is_in_brace_expansion { m_is_in_brace_expansion_spec, true };
ScopedValueRollback chars_change { m_extra_chars_not_allowed_in_barewords };
m_extra_chars_not_allowed_in_barewords.append(',');
auto rule_start = push_start();
Vector<NonnullRefPtr<AST::Node>> subexpressions;
if (next_is(","sv)) {
// Note that we don't consume the ',' here.
subexpressions.append(create<AST::StringLiteral>(String {}, AST::StringLiteral::EnclosureType::None));
} else {
auto start_expr = parse_expression();
if (start_expr) {
if (expect(".."sv)) {
if (auto end_expr = parse_expression()) {
if (end_expr->position().start_offset != start_expr->position().end_offset + 2)
end_expr->set_is_syntax_error(create<AST::SyntaxError>("Expected no whitespace between '..' and the following expression in brace expansion"_string));
return create<AST::Range>(start_expr.release_nonnull(), end_expr.release_nonnull());
}
return create<AST::Range>(start_expr.release_nonnull(), create<AST::SyntaxError>("Expected an expression to end range brace expansion with"_string, true));
}
}
if (start_expr)
subexpressions.append(start_expr.release_nonnull());
}
while (expect(',')) {
auto expr = parse_expression();
if (expr) {
subexpressions.append(expr.release_nonnull());
} else {
subexpressions.append(create<AST::StringLiteral>(String {}, AST::StringLiteral::EnclosureType::None));
}
}
if (subexpressions.is_empty())
return nullptr;
return create<AST::BraceExpansion>(move(subexpressions));
}
RefPtr<AST::Node> Parser::parse_heredoc_initiation_record()
{
if (!next_is("<<"sv))
return nullptr;
auto rule_start = push_start();
// '<' '<'
consume();
consume();
HeredocInitiationRecord record;
record.end = "<error>"_string;
RefPtr<AST::SyntaxError> syntax_error_node;
// '-' | '~'
switch (peek()) {
case '-':
record.deindent = false;
consume();
break;
case '~':
record.deindent = true;
consume();
break;
default:
restore_to(*rule_start);
return nullptr;
}
// StringLiteral | bareword
if (auto bareword = parse_bareword()) {
if (!bareword->is_bareword()) {
syntax_error_node = create<AST::SyntaxError>(TRY_OR_RESOLVE_TO_ERROR_STRING(String::formatted("Expected a bareword or a quoted string, not {}", bareword->class_name())));
} else {
if (bareword->is_syntax_error())
syntax_error_node = bareword->syntax_error_node();
else
record.end = static_cast<AST::BarewordLiteral*>(bareword.ptr())->text();
}
record.interpolate = true;
} else if (peek() == '\'') {
consume();
auto text = consume_while(is_not('\''));
bool is_error = false;
if (!expect('\''))
is_error = true;
if (is_error)
syntax_error_node = create<AST::SyntaxError>("Expected a terminating single quote"_string, true);
record.end = TRY_OR_THROW_PARSE_ERROR(String::from_utf8(text));
record.interpolate = false;
} else {
syntax_error_node = create<AST::SyntaxError>("Expected a bareword or a single-quoted string literal for heredoc end key"_string, true);
}
auto node = create<AST::Heredoc>(record.end, record.interpolate, record.deindent);
if (syntax_error_node)
node->set_is_syntax_error(*syntax_error_node);
else
node->set_is_syntax_error(*create<AST::SyntaxError>(TRY_OR_RESOLVE_TO_ERROR_STRING(String::formatted("Expected heredoc contents for heredoc with end key '{}'", node->end())), true));
record.node = node;
m_heredoc_initiations.append(move(record));
return node;
}
bool Parser::parse_heredoc_entries()
{
auto heredocs = move(m_heredoc_initiations);
m_heredoc_initiations.clear();
// Try to parse heredoc entries, as reverse recorded in the initiation records
for (auto& record : heredocs) {
auto rule_start = push_start();
if (m_rule_start_offsets.size() > max_allowed_nested_rule_depth) {
record.node->set_is_syntax_error(*create<AST::SyntaxError>(TRY_OR_RESOLVE_TO_ERROR_STRING(String::formatted("Expression nested too deep (max allowed is {})", max_allowed_nested_rule_depth))));
continue;
}
bool found_key = false;
if (!record.interpolate) {
// Since no interpolation is allowed, just read lines until we hit the key
Optional<Offset> last_line_offset;
for (;;) {
if (at_end())
break;
if (peek() == '\n')
consume();
last_line_offset = current_position();
auto line = consume_while(is_not('\n'));
if (peek() == '\n')
consume();
if (line.trim_whitespace() == record.end) {
found_key = true;
break;
}
}
if (!last_line_offset.has_value())
last_line_offset = current_position();
// Now just wrap it in a StringLiteral and set it as the node's contents
auto node = create<AST::StringLiteral>(
MUST(String::from_utf8(m_input.substring_view(rule_start->offset, last_line_offset->offset - rule_start->offset))),
AST::StringLiteral::EnclosureType::None);
if (!found_key)
node->set_is_syntax_error(*create<AST::SyntaxError>(TRY_OR_RESOLVE_TO_ERROR_STRING(String::formatted("Expected to find the heredoc key '{}', but found Eof", record.end)), true));
record.node->set_contents(move(node));
} else {
// Interpolation is allowed, so we're going to read doublequoted string innards
// until we find a line that contains the key
auto end_condition = move(m_end_condition);
found_key = false;
set_end_condition(make<Function<bool()>>([this, end = record.end, &found_key] {
if (found_key)
return true;
auto offset = current_position();
auto cond = move(m_end_condition);
ScopeGuard guard {
[&] {
m_end_condition = move(cond);
}
};
if (peek() == '\n') {
consume();
auto line = consume_while(is_not('\n'));
if (peek() == '\n')
consume();
if (line.trim_whitespace() == end) {
restore_to(offset.offset, offset.line);
found_key = true;
return true;
}
}
restore_to(offset.offset, offset.line);
return false;
}));
auto expr = parse_string_inner(StringEndCondition::Heredoc);
set_end_condition(move(end_condition));
if (found_key) {
auto offset = current_position();
if (peek() == '\n')
consume();
auto line = consume_while(is_not('\n'));
if (peek() == '\n')
consume();
if (line.trim_whitespace() != record.end)
restore_to(offset.offset, offset.line);
}
if (!expr && found_key) {
expr = create<AST::StringLiteral>(String {}, AST::StringLiteral::EnclosureType::None);
} else if (!expr) {
expr = create<AST::SyntaxError>(TRY_OR_RESOLVE_TO_ERROR_STRING(String::formatted("Expected to find a valid string inside a heredoc (with end key '{}')", record.end)), true);
} else if (!found_key) {
expr->set_is_syntax_error(*create<AST::SyntaxError>(TRY_OR_RESOLVE_TO_ERROR_STRING(String::formatted("Expected to find the heredoc key '{}'", record.end)), true));
}
record.node->set_contents(create<AST::DoubleQuotedString>(move(expr)));
}
}
return true;
}
StringView Parser::consume_while(Function<bool(char)> condition)
{
if (at_end())
return {};
auto start_offset = m_offset;
while (!at_end() && condition(peek()))
consume();
return m_input.substring_view(start_offset, m_offset - start_offset);
}
bool Parser::next_is(StringView next)
{
auto start = current_position();
auto res = expect(next);
restore_to(start.offset, start.line);
return res;
}
}
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