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range over channels.
also fix multiple-evaluation bug in range over arrays. R=ken OCL=26576 CL=26576
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parent
386845b23f
commit
54aa835b44
@ -3184,7 +3184,7 @@ Node*
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dorange(Node *nn)
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{
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Node *k, *v, *m;
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Node *n, *hk, *on, *r, *a;
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Node *n, *hv, *hc, *ha, *hk, *on, *r, *a;
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Type *t, *th;
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int local;
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@ -3212,16 +3212,23 @@ dorange(Node *nn)
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goto ary;
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if(t->etype == TMAP)
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goto map;
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if(t->etype == TCHAN)
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goto chan;
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yyerror("range must be over map/array");
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goto out;
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ary:
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hk = nod(OXXX, N, N); // hidden key
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tempname(hk, types[TINT]); // maybe TINT32
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tempname(hk, types[TINT]);
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ha = nod(OXXX, N, N); // hidden array
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tempname(ha, t);
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n->ninit = nod(OAS, hk, nodintconst(0));
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n->ntest = nod(OLT, hk, nod(OLEN, m, N));
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n->ninit = list(nod(OAS, ha, m), n->ninit);
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n->ntest = nod(OLT, hk, nod(OLEN, ha, N));
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n->nincr = nod(OASOP, hk, nodintconst(1));
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n->nincr->etype = OADD;
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@ -3233,7 +3240,7 @@ ary:
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if(local)
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v = old2new(v, t->type);
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n->nbody = list(n->nbody,
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nod(OAS, v, nod(OINDEX, m, hk)) );
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nod(OAS, v, nod(OINDEX, ha, hk)) );
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}
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addtotop(n);
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goto out;
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@ -3288,7 +3295,29 @@ map:
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r = nod(OADDR, hk, N);
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r = nod(OCALL, on, r);
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n->nbody = nod(OAS, nod(OLIST, k, v), r);
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goto out;
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chan:
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if(v != N)
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yyerror("chan range can only have one variable");
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hc = nod(OXXX, N, N); // hidden chan
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tempname(hc, t);
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hv = nod(OXXX, N, N); // hidden value
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tempname(hv, t->type);
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n->ninit = list(
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nod(OAS, hc, m),
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nod(OAS, hv, nod(ORECV, hc, N))
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);
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n->ntest = nod(ONOT, nod(OCLOSED, hc, N), N);
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n->nincr = nod(OAS, hv, nod(ORECV, hc, N));
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if(local)
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k = old2new(k, hv->type);
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n->nbody = nod(OAS, k, hv);
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addtotop(n);
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goto out;
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out:
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@ -19,8 +19,7 @@ func Generate(ch chan<- int) {
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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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for i := range in { // Loop over values received 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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@ -32,6 +31,7 @@ func Sieve(primes chan<- int) {
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ch := make(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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// Note that ch is different on each iteration.
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prime := <-ch;
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primes <- prime;
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ch1 := make(chan int);
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@ -45,7 +45,7 @@ func main() {
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go Sieve(primes);
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a := []int{2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97};
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for i := 0; i < len(a); i++ {
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if <-primes != a[i] { panic(a[i])}
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if x := <-primes; x != a[i] { panic(x, " != ", a[i]) }
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}
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sys.Exit(0);
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}
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59
test/range.go
Normal file
59
test/range.go
Normal file
@ -0,0 +1,59 @@
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// $G $D/$F.go && $L $F.$A && ./$A.out
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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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// test range over channels
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func gen(c chan int, lo, hi int) {
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for i := lo; i <= hi; i++ {
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c <- i;
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}
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close(c);
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}
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func seq(lo, hi int) chan int {
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c := make(chan int);
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go gen(c, lo, hi);
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return c;
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}
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func testchan() {
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s := "";
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for i := range seq('a', 'z') {
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s += string(i);
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}
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if s != "abcdefghijklmnopqrstuvwxyz" {
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panicln("Wanted lowercase alphabet; got", s);
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}
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}
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// test that range over array only evaluates
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// the expression after "range" once.
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var nmake = 0;
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func makearray() []int {
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nmake++;
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return []int{1,2,3,4,5};
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}
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func testarray() {
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s := 0;
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for k, v := range makearray() {
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s += v;
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}
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if nmake != 1 {
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panicln("range called makearray", nmake, "times");
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}
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if s != 15 {
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panicln("wrong sum ranging over makearray");
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}
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}
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func main() {
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testchan();
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testarray();
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}
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