From 30ee2227daf95d51b602b77eb45e352d3b8e666d Mon Sep 17 00:00:00 2001
From: "ben.franksen" <ben.franksen@online.de>
Date: Mon, 22 Aug 2011 10:37:06 +0000
Subject: [PATCH] added support for the C comma operator
As turned out, the 2.0.x branch supported this, so it is added
for compatibility.
---
documentation/Reference.txt | 43 ++++++++++++++++++++++------------
src/snc/snl.lem | 42 +++++++++++++++++++--------------
test/validate/Makefile | 1 +
test/validate/commaOperator.st | 30 ++++++++++++++++++++++++
4 files changed, 83 insertions(+), 33 deletions(-)
create mode 100644 test/validate/commaOperator.st
diff --git a/documentation/Reference.txt b/documentation/Reference.txt
index 1aa97e44..bfcb11b3 100644
--- a/documentation/Reference.txt
+++ b/documentation/Reference.txt
@@ -799,12 +799,12 @@ Statements
statement: "state" `identifier` ";"
statement: `c_code`
statement: `block`
- statement: "if" "(" `expr` ")" `statement`
- statement: "if" "(" `expr` ")" `statement` "else" `statement`
- statement: "while" "(" `expr` ")" `statement`
+ statement: "if" "(" `comma_expr` ")" `statement`
+ statement: "if" "(" `comma_expr` ")" `statement` "else" `statement`
+ statement: "while" "(" `comma_expr` ")" `statement`
statement: `for_statement`
statement: `opt_expr` ";"
- for_statement: "for" "(" `exprs` ";" `opt_expr` ";" `exprs` ")" `statement`
+ for_statement: "for" "(" `opt_expr` ";" `opt_expr` ";" `opt_expr` ")" `statement`
As can be seen, most C statements are supported. Not supported are
the switch/case statement and the return statement.
@@ -836,14 +836,14 @@ Parenthesized Expression
~~~~~~~~~~~~~~~~~~~~~~~~
.. productionlist::
- expr: "(" `expr` ")"
+ expr: "(" `comma_expr` ")"
Primary Expression Operators
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
.. productionlist::
- expr: `identifier` "(" `exprs` ")"
- expr: "exit" "(" `exprs` ")"
+ expr: `identifier` "(" `args` ")"
+ expr: "exit" "(" `args` ")"
expr: `expr` "[" `expr` "]"
expr: `expr` "." `expr`
expr: `expr` "->" `expr`
@@ -924,17 +924,30 @@ Assignment Operators
These operators are right-associative.
-Expression List
-~~~~~~~~~~~~~~~
+Comma Operator
+~~~~~~~~~~~~~~
+
+.. productionlist::
+ comma_expr: `comma_expr` "," `expr`
+ comma_expr: `expr`
+ opt_expr: `comma_expr`
+ opt_expr:
+
+The comma operator is left associative. An :token:`opt_expr` is
+an optional :token:`comma_expr`; it appears, for instance, inside
+a :token:`for_statement`.
+
+Argument List
+~~~~~~~~~~~~~
.. productionlist::
- exprs: `exprs` "," `expr`
- exprs: `expr`
- exprs:
+ args: `args` "," `expr`
+ args: `expr`
+ args:
-Comma separated expression lists are not expressions (in SNL), since
-SNL does not support the comma operator. However, they appear as parts
-of expressions and statements, and then have the same meaning as in C.
+Function argument lists look exactly like chained application of the
+comma operator, which is why application of the comma operator in an
+argument list must be grouped by parentheses.
.. _BuiltinFunctions:
diff --git a/src/snc/snl.lem b/src/snc/snl.lem
index e183e1b6..a489e9b4 100644
--- a/src/snc/snl.lem
+++ b/src/snc/snl.lem
@@ -55,12 +55,10 @@ in the file LICENSE that is included with this distribution.
// PRE and POST are pseudo tokens, they only for the
// precedence declaration.
-// We do not support the comma operator, except
-// in for(;;), where it is built-in.
+// The comma operator is implemented as an extra production,
+// so we need no explicit precedence for it.
// %left COMMA.
-
-%right EQUAL ADDEQ SUBEQ ANDEQ OREQ
- DIVEQ MULEQ MODEQ LSHEQ RSHEQ XOREQ.
+%right EQUAL ADDEQ SUBEQ ANDEQ OREQ DIVEQ MULEQ MODEQ LSHEQ RSHEQ XOREQ.
%right QUESTION COLON.
%left OROR.
%left ANDAND.
@@ -182,6 +180,7 @@ direct_declarator(p) ::= direct_declarator(x) subscript(s).
{ p = decl_postfix_array(x, s.str); }
// Initializer
+// Note: comma operator not allowed in 'expr'.
init_expr(p) ::= LBRACE(t) init_exprs(x) RBRACE.{ p = expr(E_INIT, t, x); }
init_expr(p) ::= expr(x). { p = x; }
@@ -303,22 +302,26 @@ statement(p) ::= STATE NAME(t) SEMICOLON. { p = expr(S_CHANGE, t); }
statement(p) ::= c_code(x). { p = x; }
statement(p) ::= LBRACE(t) block_defns(ds) statements(xs) RBRACE.
{ p = expr(S_CMPND, t, ds, xs); }
-statement(p) ::= IF(t) LPAREN expr(c) RPAREN statement(th).
+statement(p) ::= IF(t) LPAREN comma_expr(c) RPAREN statement(th).
{ p = expr(S_IF, t, c, th, 0); }
-statement(p) ::= IF(t) LPAREN expr(c) RPAREN statement(th) ELSE statement(el).
+statement(p) ::= IF(t) LPAREN comma_expr(c) RPAREN statement(th) ELSE statement(el).
{ p = expr(S_IF, t, c, th, el); }
-statement(p) ::= WHILE(t) LPAREN expr(c) RPAREN statement(x).
+statement(p) ::= WHILE(t) LPAREN comma_expr(c) RPAREN statement(x).
{ p = expr(S_WHILE, t, c, x); }
statement(p) ::= for_statement(x). { p = x; }
statement(p) ::= opt_expr(x) SEMICOLON(t). { p = expr(S_STMT, t, x); }
for_statement(p) ::=
FOR(for) LPAREN
- exprs(init) SEMICOLON opt_expr(cond) SEMICOLON exprs(iter)
+ opt_expr(init) SEMICOLON opt_expr(cond) SEMICOLON opt_expr(iter)
RPAREN statement(st). { p = expr(S_FOR, for, init, cond, iter, st); }
// Expressions
+// Note: the non-terminal 'expr' does not include application of the comma operator.
+// Comma separated lists of 'expr' can be: function arguments (non-terminal
+// 'args')and applications of the comma operator (non-terminal 'comma_expr').
+
// Atomic
expr(p) ::= INTCON(x). { p = expr(E_CONST, x); }
expr(p) ::= FPCON(x). { p = expr(E_CONST, x); }
@@ -326,11 +329,11 @@ expr(p) ::= string(x). { p = x; }
expr(p) ::= variable(v). { p = expr(E_VAR, v); }
// Parenthesized
-expr(p) ::= LPAREN(t) expr(x) RPAREN. { p = expr(E_PAREN, t, x); }
+expr(p) ::= LPAREN(t) comma_expr(x) RPAREN. { p = expr(E_PAREN, t, x); }
// Primary Expression and Unary Postfix Operators
-expr(p) ::= NAME(t) LPAREN exprs(xs) RPAREN. [POST] { p = expr(E_FUNC, t, xs); }
-expr(p) ::= EXIT(t) LPAREN exprs(xs) RPAREN. [POST] { p = expr(E_FUNC, t, xs); }
+expr(p) ::= NAME(t) LPAREN args(xs) RPAREN. [POST] { p = expr(E_FUNC, t, xs); }
+expr(p) ::= EXIT(t) LPAREN args(xs) RPAREN. [POST] { p = expr(E_FUNC, t, xs); }
expr(p) ::= expr(x) LBRACKET(t) expr(y) RBRACKET.[POST] { p = expr(E_SUBSCR, t, x, y); }
expr(p) ::= expr(x) PERIOD(t) expr(y). [POST] { p = expr(E_BINOP, t, x, y); }
expr(p) ::= expr(x) POINTER(t) expr(y). [POST] { p = expr(E_BINOP, t, x, y); }
@@ -384,15 +387,18 @@ expr(p) ::= expr(x) LSHEQ(t) expr(y). { p = expr(E_BINOP, t, x, y); }
expr(p) ::= expr(x) RSHEQ(t) expr(y). { p = expr(E_BINOP, t, x, y); }
expr(p) ::= expr(x) XOREQ(t) expr(y). { p = expr(E_BINOP, t, x, y); }
-// Comma, left-to-right, not supported
-// expr(p) ::= expr(x) COMMA(t) expr(y). { p = expr(E_BINOP, t, x, y); }
+// Comma, left-to-right
+comma_expr(p) ::= comma_expr(xs) COMMA(t) expr(x). { p = expr(E_BINOP, t, xs, x); }
+comma_expr(p) ::= expr(x). { p = x; }
-opt_expr(p) ::= expr(x). { p = x; }
+opt_expr(p) ::= comma_expr(x). { p = x; }
opt_expr(p) ::= . { p = 0; }
-exprs(p) ::= exprs(xs) COMMA expr(x). { p = link_expr(xs, x); }
-exprs(p) ::= expr(x). { p = x; }
-exprs(p) ::= . { p = 0; }
+// Function arguments
+// Ssyntactically the same as opt_expr but interpreted differently.
+args(p) ::= args(xs) COMMA expr(x). { p = link_expr(xs, x); }
+args(p) ::= expr(x). { p = x; }
+args(p) ::= . { p = 0; }
string(p) ::= STRCON(t). { p = expr(E_STRING, t); }
diff --git a/test/validate/Makefile b/test/validate/Makefile
index 2e2f88cc..e7044a34 100644
--- a/test/validate/Makefile
+++ b/test/validate/Makefile
@@ -37,6 +37,7 @@ REGRESSION_TESTS_WITH_DB += norace
REGRESSION_TESTS_WITHOUT_DB += array
REGRESSION_TESTS_WITHOUT_DB += assign
REGRESSION_TESTS_WITHOUT_DB += change
+REGRESSION_TESTS_WITHOUT_DB += commaOperator
REGRESSION_TESTS_WITHOUT_DB += local
REGRESSION_TESTS_WITHOUT_DB += pvSync
REGRESSION_TESTS_WITHOUT_DB += safeMonitor
diff --git a/test/validate/commaOperator.st b/test/validate/commaOperator.st
new file mode 100644
index 00000000..09439b1e
--- /dev/null
+++ b/test/validate/commaOperator.st
@@ -0,0 +1,30 @@
+/*************************************************************************\
+Copyright (c) 2010-2011 Helmholtz-Zentrum Berlin f. Materialien
+ und Energie GmbH, Germany (HZB)
+This file is distributed subject to a Software License Agreement found
+in the file LICENSE that is included with this distribution.
+\*************************************************************************/
+program commaOperatorTest
+
+%%#include "../testSupport.h"
+
+entry {
+ testPlan(4);
+}
+
+ss myss {
+ state doit {
+ when () {
+ int i = 0;
+ /* check associativity (evaluation order) and result */
+ testOk1(((i = 1), testOk1(i==1), (i = 2), testOk1(i==2),
+ (i = 3)) == 3);
+ testOk1(i == 3);
+ } exit
+ }
+}
+
+exit {
+ testDone();
+ seq_test_done();
+}
--
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