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https://github.com/golang/go
synced 2024-09-04 15:34:21 +00:00
- added 'nil' keyword to lang doc
(did not add 'true' and 'false' because I think these don't need to be keywords, they can be recreated from whole cloth) - added 'new' syntax to expressions (this is needed because of the type as 1st argument - the expression list is probably not yet implemented, but I think we may want it eventually) - removed optional ';'s in sieve example - make it more concise - fixed several bugs in go.atg, no parses sieve - added sieve as test case SVN=112135
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@ -154,7 +154,7 @@ Here is a complete example Go program that implements a concurrent prime sieve:
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// Send the sequence 2, 3, 4, ... to channel 'ch'.
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func Generate(ch *chan> int) {
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for i := 2; ; i++ {
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>ch = i; // Send 'i' to channel 'ch'.
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>ch = i // Send 'i' to channel 'ch'.
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}
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}
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@ -164,7 +164,7 @@ Here is a complete example Go program that implements a concurrent prime sieve:
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for {
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i := <in; // Receive value of new variable 'i' from 'in'.
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if i % prime != 0 {
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>out = i; // Send 'i' to channel 'out'.
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>out = i // Send 'i' to channel 'out'.
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}
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}
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}
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@ -178,12 +178,12 @@ Here is a complete example Go program that implements a concurrent prime sieve:
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printf("%d\n", prime);
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ch1 := new(chan int);
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go Filter(ch, ch1, prime);
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ch = ch1;
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ch = ch1
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}
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}
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func Main() {
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Sieve();
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Sieve()
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}
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@ -822,7 +822,7 @@ Literals
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----
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Literal = BasicLit | CompoundLit .
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BasicLit = char_lit | string_lit | int_lit | float_lit .
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BasicLit = char_lit | string_lit | int_lit | float_lit | "nil" .
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CompoundLit = ArrayLit | MapLit | StructLit | FunctionLit .
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@ -993,11 +993,12 @@ Expression syntax is based on that of C but with fewer precedence levels.
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PrimaryExpr =
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identifier | Literal | "(" Expression ")" | "iota" |
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Call | Conversion |
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Call | Conversion | Allocation |
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Expression "[" Expression [ ":" Expression ] "]" | Expression "." identifier .
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Call = Expression "(" [ ExpressionList ] ")" .
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Conversion = TypeName "(" [ ExpressionList ] ")" .
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Allocation = "new" "(" Type [ "," ExpressionList ] ")" .
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binary_op = log_op | rel_op | add_op | mul_op .
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log_op = "||" | "&&" .
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42
tests/sieve.go
Normal file
42
tests/sieve.go
Normal file
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@ -0,0 +1,42 @@
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// $G $F.go && $L $F.$A # don't run it - goes forever
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// Copyright 2009 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package Main
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// Send the sequence 2, 3, 4, ... to channel 'ch'.
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func Generate(ch *chan> int) {
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for i := 2; ; i++ {
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>ch = i // Send 'i' to channel 'ch'.
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}
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}
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// Copy the values from channel 'in' to channel 'out',
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// removing those divisible by 'prime'.
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func Filter(in *chan< int, out *chan> int, prime int) {
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for {
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i := <in; // Receive value of new variable 'i' from 'in'.
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if i % prime != 0 {
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>out = i // Send 'i' to channel 'out'.
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}
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}
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}
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// The prime sieve: Daisy-chain Filter processes together.
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func Sieve() {
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ch := new(chan int); // Create a new channel.
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go Generate(ch); // Start Generate() as a subprocess.
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for {
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prime := <ch;
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printf("%d\n", prime);
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ch1 := new(chan int);
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go Filter(ch, ch1, prime);
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ch = ch1
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}
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}
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func Main() {
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Sieve()
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}
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