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Revise spec to agree with implementations for meaning of getter/variable and setter references. While the actual difference were only in a few odd cases, the new text should also be clearer.

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R=hausner@google.com, lrn@google.com

Review URL: https://codereview.chromium.org//177283007

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart@33287 260f80e4-7a28-3924-810f-c04153c831b5
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gbracha@google.com 2014-03-04 18:37:37 +00:00
parent 762a05195b
commit 6d58ce9bfe
1 changed files with 26 additions and 16 deletions
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42
docs/language/dartLangSpec.tex
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@ -3372,21 +3372,24 @@ An assignment changes the value associated with a mutable variable or property.
Evaluation of an assignment $a$ of the form $v$ \code{=} $e$ proceeds as follows:
If there is neither a local variable declaration with name $v$ nor a setter declaration with name $v=$ in the lexical scope enclosing $a$, then:
\begin{itemize}
\item If $a$ occurs inside a top level or static function (be it function, method, getter, or setter) or variable initializer, evaluation of $a$ causes $e$ to be evaluated, after which a \code{NoSuchMethodError} is thrown.
\item Otherwise, the assignment is equivalent to the assignment \code{ \THIS{}.$v$ = $e$}.
\end{itemize}
%If there is neither a local variable declaration with name $v$ nor a setter declaration with name $v=$ in the lexical scope enclosing $a$, then:
%\begin{itemize}
% \item If $a$ occurs inside a top level or static function (be it function, method, getter, or setter) or variable initializer, evaluation of $a$ causes $e$ to be evaluated, after which a \code{NoSuchMethodError} is thrown.
% \item Otherwise, the assignment is equivalent to the assignment \code{ \THIS{}.$v$ = $e$}.
% \end{itemize}
Otherwise, let $d$ be the innermost declaration whose name is $v$, if it exists.
%Otherwise,
If $d$ is the declaration of a local variable, the expression $e$ is evaluated to an object $o$. Then, the variable $v$ is bound to $o$.
% unless $v$ is \FINAL{}, in which case a \code{NoSuchMethodError} is thrown (even if there is a noSuchMethod).
The value of the assignment expression is $o$.
Let $d$ be the innermost declaration whose name is $v$ or $v=$, if it exists.
If $d$ is the declaration of a library variable, the expression $e$ is evaluated to an object $o$. Then the setter $v=$ is invoked with its formal parameter bound to $o$. The value of the assignment expression is $o$.
If $d$ is the declaration of a local variable, the expression $e$ is evaluated to an object $o$. Then, the variable $v$ is bound to $o$ unless $v$ is \FINAL{} or \CONST{}, in which case a dynamic error occurs.
If no error occurs, the value of the assignment expression is $o$.
Otherwise, if $d$ is the declaration of a static variable in class $C$, then the assignment is equivalent to the assignment \code{$C.v$ = $e$}.
If $d$ is the declaration of a library variable, top level getter or top level setter, the expression $e$ is evaluated to an object $o$. Then the setter $v=$ is invoked with its formal parameter bound to $o$. The value of the assignment expression is $o$.
Otherwise, if $d$ is the declaration of a static variable, static getter or static setter in class $C$, then the assignment is equivalent to the assignment \code{$C.v$ = $e$}.
Otherwise, If $a$ occurs inside a top level or static function (be it function, method, getter, or setter) or variable initializer, evaluation of $a$ causes $e$ to be evaluated, after which a \code{NoSuchMethodError} is thrown.
Otherwise, the assignment is equivalent to the assignment \code{ \THIS{}.$v$ = $e$}.
@ -3927,7 +3930,8 @@ Built-in identifiers are identifiers that are used as keywords in Dart, but are
Evaluation of an identifier expression $e$ of the form $id$ proceeds as follows:
Let $d$ be the innermost declaration in the enclosing lexical scope whose name is $id$. If no such declaration exists in the lexical scope, let $d$ be the declaration of the inherited member named $id$ if it exists.
Let $d$ be the innermost declaration in the enclosing lexical scope whose name is $id$ or $id=$. If no such declaration exists in the lexical scope, let $d$ be the declaration of the inherited member named $id$ if it exists.
%If no such member exists, let $d$ be the declaration of the static member name $id$ declared in a superclass of the current class, if it exists.
\begin{itemize}
@ -3945,8 +3949,8 @@ Let $d$ be the innermost declaration in the enclosing lexical scope whose name i
\item If $d$ is a local variable or formal parameter then $e$ evaluates to the current binding of $id$.
%\item If $d$ is a library variable, local variable, or formal parameter, then $e$ evaluates to the current binding of $id$. \commentary{This case also applies if d is a library or local function declaration, as these are equivalent to function-valued variable declarations.}
\item If $d$ is a static method, top-level function or local function then $e$ evaluates to the function defined by $d$.
\item If $d$ is the declaration of a static variable or static getter declared in class $C$, then $e$ is equivalent to the getter invocation (\ref{getterInvocation}) $C.id$.
\item If $d$ is the declaration of a library variable or top-level getter, then $e$ is equivalent to the getter invocation $id$.
\item If $d$ is the declaration of a static variable, static getter or static setter declared in class $C$, then $e$ is equivalent to the getter invocation (\ref{getterInvocation}) $C.id$.
\item If $d$ is the declaration of a library variable, top-level getter or top-level setter, then $e$ is equivalent to the getter invocation $id$.
\item Otherwise, if $e$ occurs inside a top level or static function (be it function, method, getter, or setter) or variable initializer, evaluation of $e$ causes a\code{NoSuchMethod} to be thrown.
\item Otherwise, $e$ is equivalent to the property extraction (\ref{propertyExtraction}) \THIS{}.$id$.
% This implies that referring to an undefined static getter by simple name is an error, whereas doing so by qualified name is only a warning. Same with assignments. Revise?
@ -3958,12 +3962,18 @@ The static type of $e$ is determined as follows:
\item If $d$ is a class, type alias or type parameter the static type of $e$ is \code{Type}.
\item If $d$ is a local variable or formal parameter the static type of $e$ is the type of the variable $id$, unless $id$ is known to have some type $T$, in which case the static type of $e$ is $T$, provided that $T$ is more specific than any other type $S$ such that $v$ is known to have type $S$.
\item If $d$ is a static method, top-level function or local function the static type of $e$ the function type defined by $d$.
\item If $d$ is the declaration of a static variable or static getter declared in class $C$, the static type of $e$ the static type of the getter invocation (\ref{getterInvocation}) $C.id$.
\item If $d$ is the declaration of a static variable or static getter declared in class $C$, the static type of $e$ the static type of the getter invocation (\ref{getterInvocation}) $C.id$.
\item If $d$ is the declaration of a library variable or top-level getter, the static type of $e$ is the static type of the getter invocation $id$.
\item Otherwise, if $e$ occurs inside a top level or static function (be it function, method, getter, or setter) or variable initializer, the static type of $e$ is \DYNAMIC{}.
\item Otherwise, the static type of $e$ is the type of the property extraction (\ref{propertyExtraction}) \THIS{}.$id$.
\end{itemize}
\commentary{Note that if one declares a setter, we bind to the corresponding getter even if it does not exist.}
\rationale{
This prevents situations where one uses uncorrelated setters and getters. The intent is to prevent errors when a getter in a surrounding scope is used accidentally.
}
It is a static warning if an identifier expression $id$ occurs inside a top level or static function (be it function, method, getter, or setter) or variable initializer and there is no declaration $d$ with name $id$ in the lexical scope enclosing the expression.
\subsection{ Type Test}
@ -4833,7 +4843,7 @@ It is a dynamic type error if $o$ is not of type \code{bool} or of type \code{Fu
A Dart program consists of one or more libraries, and may be built out of one or more {\em compilation units}. A compilation unit may be a library or a part (\ref{parts}).
A library consists of (a possibly empty) set of imports, a set of exports, and a set of top-level declarations. A top-level declaration is either a class (\ref{classes}), a type alias declaration (\ref{typedef}), a function (\ref{functions}) or a variable declaration (\ref{variables}). The members of a library $L$ are those top level declarations given within a $L$.
A library consists of (a possibly empty) set of imports, a set of exports, and a set of top-level declarations. A top-level declaration is either a class (\ref{classes}), a type alias declaration (\ref{typedef}), a function (\ref{functions}) or a variable declaration (\ref{variables}). The members of a library $L$ are those top level declarations given within $L$.
\begin{grammar}
{\bf topLevelDefinition:}classDefinition;