lix/src/libexpr/parser.y
Eelco Dolstra c5baaafae6 * Replaced the SDF parser by a substantially faster Bison/Flex
parser (roughly 80x faster).

  The absolutely latest version of Bison (1.875c) is required for
  reentrant GLR support, as well as a recent version of Flex (say,
  2.5.31).  Note that most Unix distributions ship with the
  prehistoric Flex 2.5.4, which doesn't support reentrancy.
2004-01-30 15:21:42 +00:00

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%glr-parser
%pure-parser
%locations
%error-verbose
%parse-param { yyscan_t scanner }
%parse-param { void * data }
%lex-param { yyscan_t scanner }
%{
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <aterm2.h>
#include "parser-tab.h"
#include "lexer-tab.h"
void setParseResult(void * data, ATerm t);
void parseError(void * data, char * error, int line, int column);
ATerm absParsedPath(void * data, ATerm t);
void yyerror(YYLTYPE * loc, yyscan_t scanner, void * data, char * s)
{
parseError(data, s, loc->first_line, loc->first_column);
}
%}
%union {
ATerm t;
ATermList ts;
}
%type <t> start expr expr_function expr_assert expr_op
%type <t> expr_app expr_select expr_simple bind formal
%type <ts> binds expr_list formals
%token <t> ID INT STR PATH URI
%token IF THEN ELSE ASSERT LET REC EQ NEQ AND OR IMPL
%nonassoc IMPL
%left OR
%left AND
%nonassoc EQ NEQ
%left NEG
%%
start: expr { setParseResult(data, $1); };
expr: expr_function;
expr_function
: '{' formals '}' ':' expr_function
{ $$ = ATmake("Function(<term>, <term>)", $2, $5); }
| expr_assert
;
expr_assert
: ASSERT expr ';' expr_assert
{ $$ = ATmake("Assert(<term>, <term>)", $2, $4); }
| expr_op
;
expr_op
: '!' expr_op %prec NEG { $$ = ATmake("OpNot(<term>)", $2); }
| expr_op EQ expr_op { $$ = ATmake("OpEq(<term>, <term>)", $1, $3); }
| expr_op NEQ expr_op { $$ = ATmake("OpNEq(<term>, <term>)", $1, $3); }
| expr_op AND expr_op { $$ = ATmake("OpAnd(<term>, <term>)", $1, $3); }
| expr_op OR expr_op { $$ = ATmake("OpOr(<term>, <term>)", $1, $3); }
| expr_op IMPL expr_op { $$ = ATmake("OpImpl(<term>, <term>)", $1, $3); }
| expr_app
;
expr_app
: expr_app expr_select
{ $$ = ATmake("Call(<term>, <term>)", $1, $2); }
| expr_select { $$ = $1; }
;
expr_select
: expr_select '.' ID
{ $$ = ATmake("Select(<term>, <term>)", $1, $3); }
| expr_simple { $$ = $1; }
;
expr_simple
: ID { $$ = ATmake("Var(<term>)", $1); }
| STR { $$ = ATmake("Str(<term>)", $1); }
| PATH { $$ = ATmake("Path(<term>)", absParsedPath(data, $1)); }
| URI { $$ = ATmake("Uri(<term>)", $1); }
| '(' expr ')' { $$ = $2; }
| LET '{' binds '}' { $$ = ATmake("LetRec(<term>)", $3); }
| REC '{' binds '}' { $$ = ATmake("Rec(<term>)", $3); }
| '{' binds '}' { $$ = ATmake("Attrs(<term>)", $2); }
| '[' expr_list ']' { $$ = ATmake("List(<term>)", $2); }
| IF expr THEN expr ELSE expr
{ $$ = ATmake("If(<term>, <term>, <term>)", $2, $4, $6); }
;
binds
: binds bind { $$ = ATinsert($1, $2); }
| { $$ = ATempty; }
;
bind
: ID '=' expr ';'
{ $$ = ATmake("Bind(<term>, <term>)", $1, $3); }
;
expr_list
: expr_select expr_list { $$ = ATinsert($2, $1); }
/* yes, this is right-recursive, but it doesn't matter since
otherwise we would need ATreverse which requires unbounded
stack space */
| { $$ = ATempty; }
;
formals
: formal ',' formals { $$ = ATinsert($3, $1); } /* idem - right recursive */
| formal { $$ = ATinsert(ATempty, $1); }
;
formal
: ID { $$ = ATmake("NoDefFormal(<term>)", $1); }
| ID '?' expr { $$ = ATmake("DefFormal(<term>, <term>)", $1, $3); }
;
%%