awk.y

早期freebsd实现

/*
 * awk.y --- yacc/bison parser
 */

/* 
 * Copyright (C) 1986, 1988, 1989, 1991, 1992 the Free Software Foundation, Inc.
 * 
 * This file is part of GAWK, the GNU implementation of the
 * AWK Progamming Language.
 * 
 * GAWK is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 * 
 * GAWK is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with GAWK; see the file COPYING.  If not, write to
 * the Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

%{
#ifdef DEBUG
#define YYDEBUG 12
#endif

#include "awk.h"

static void yyerror (); /* va_alist */
static char *get_src_buf P((void));
static int yylex P((void));
static NODE *node_common P((NODETYPE op));
static NODE *snode P((NODE *subn, NODETYPE op, int sindex));
static NODE *mkrangenode P((NODE *cpair));
static NODE *make_for_loop P((NODE *init, NODE *cond, NODE *incr));
static NODE *append_right P((NODE *list, NODE *new));
static void func_install P((NODE *params, NODE *def));
static void pop_var P((NODE *np, int freeit));
static void pop_params P((NODE *params));
static NODE *make_param P((char *name));
static NODE *mk_rexp P((NODE *exp));

static int want_assign;		/* lexical scanning kludge */
static int want_regexp;		/* lexical scanning kludge */
static int can_return;		/* lexical scanning kludge */
static int io_allowed = 1;	/* lexical scanning kludge */
static char *lexptr;		/* pointer to next char during parsing */
static char *lexend;
static char *lexptr_begin;	/* keep track of where we were for error msgs */
static char *lexeme;		/* beginning of lexeme for debugging */
static char *thisline = NULL;
#define YYDEBUG_LEXER_TEXT (lexeme)
static int param_counter;
static char *tokstart = NULL;
static char *token = NULL;
static char *tokend;

NODE *variables[HASHSIZE];

extern char *source;
extern int sourceline;
extern struct src *srcfiles;
extern int numfiles;
extern int errcount;
extern NODE *begin_block;
extern NODE *end_block;
%}

%union {
	long lval;
	AWKNUM fval;
	NODE *nodeval;
	NODETYPE nodetypeval;
	char *sval;
	NODE *(*ptrval)();
}

%type <nodeval> function_prologue function_body
%type <nodeval> rexp exp start program rule simp_exp
%type <nodeval> non_post_simp_exp
%type <nodeval> pattern 
%type <nodeval>	action variable param_list
%type <nodeval>	rexpression_list opt_rexpression_list
%type <nodeval>	expression_list opt_expression_list
%type <nodeval>	statements statement if_statement opt_param_list 
%type <nodeval> opt_exp opt_variable regexp 
%type <nodeval> input_redir output_redir
%type <nodetypeval> print
%type <sval> func_name
%type <lval> lex_builtin

%token <sval> FUNC_CALL NAME REGEXP
%token <lval> ERROR
%token <nodeval> YNUMBER YSTRING
%token <nodetypeval> RELOP APPEND_OP
%token <nodetypeval> ASSIGNOP MATCHOP NEWLINE CONCAT_OP
%token <nodetypeval> LEX_BEGIN LEX_END LEX_IF LEX_ELSE LEX_RETURN LEX_DELETE
%token <nodetypeval> LEX_WHILE LEX_DO LEX_FOR LEX_BREAK LEX_CONTINUE
%token <nodetypeval> LEX_PRINT LEX_PRINTF LEX_NEXT LEX_EXIT LEX_FUNCTION
%token <nodetypeval> LEX_GETLINE
%token <nodetypeval> LEX_IN
%token <lval> LEX_AND LEX_OR INCREMENT DECREMENT
%token <lval> LEX_BUILTIN LEX_LENGTH

/* these are just yylval numbers */

/* Lowest to highest */
%right ASSIGNOP
%right '?' ':'
%left LEX_OR
%left LEX_AND
%left LEX_GETLINE
%nonassoc LEX_IN
%left FUNC_CALL LEX_BUILTIN LEX_LENGTH
%nonassoc MATCHOP
%nonassoc RELOP '<' '>' '|' APPEND_OP
%left CONCAT_OP
%left YSTRING YNUMBER
%left '+' '-'
%left '*' '/' '%'
%right '!' UNARY
%right '^'
%left INCREMENT DECREMENT
%left '$'
%left '(' ')'
%%

start
	: opt_nls program opt_nls
		{ expression_value = $2; }
	;

program
	: rule
		{ 
			if ($1 != NULL)
				$$ = $1;
			else
				$$ = NULL;
			yyerrok;
		}
	| program rule
		/* add the rule to the tail of list */
		{
			if ($2 == NULL)
				$$ = $1;
			else if ($1 == NULL)
				$$ = $2;
			else {
				if ($1->type != Node_rule_list)
					$1 = node($1, Node_rule_list,
						(NODE*)NULL);
				$$ = append_right ($1,
				   node($2, Node_rule_list,(NODE *) NULL));
			}
			yyerrok;
		}
	| error	{ $$ = NULL; }
	| program error { $$ = NULL; }
	;

rule
	: LEX_BEGIN { io_allowed = 0; }
	  action
	  {
		if (begin_block) {
			if (begin_block->type != Node_rule_list)
				begin_block = node(begin_block, Node_rule_list,
					(NODE *)NULL);
			(void) append_right (begin_block, node(
			    node((NODE *)NULL, Node_rule_node, $3),
			    Node_rule_list, (NODE *)NULL) );
		} else
			begin_block = node((NODE *)NULL, Node_rule_node, $3);
		$$ = NULL;
		io_allowed = 1;
		yyerrok;
	  }
	| LEX_END { io_allowed = 0; }
	  action
	  {
		if (end_block) {
			if (end_block->type != Node_rule_list)
				end_block = node(end_block, Node_rule_list,
					(NODE *)NULL);
			(void) append_right (end_block, node(
			    node((NODE *)NULL, Node_rule_node, $3),
			    Node_rule_list, (NODE *)NULL));
		} else
			end_block = node((NODE *)NULL, Node_rule_node, $3);
		$$ = NULL;
		io_allowed = 1;
		yyerrok;
	  }
	| LEX_BEGIN statement_term
	  {
		warning("BEGIN blocks must have an action part");
		errcount++;
		yyerrok;
	  }
	| LEX_END statement_term
	  {
		warning("END blocks must have an action part");
		errcount++;
		yyerrok;
	  }
	| pattern action
		{ $$ = node ($1, Node_rule_node, $2); yyerrok; }
	| action
		{ $$ = node ((NODE *)NULL, Node_rule_node, $1); yyerrok; }
	| pattern statement_term
		{
		  $$ = node ($1,
			     Node_rule_node,
			     node(node(node(make_number(0.0),
					    Node_field_spec,
					    (NODE *) NULL),
					Node_expression_list,
					(NODE *) NULL),
				  Node_K_print,
				  (NODE *) NULL));
		  yyerrok;
		}
	| function_prologue function_body
		{
			func_install($1, $2);
			$$ = NULL;
			yyerrok;
		}
	;

func_name
	: NAME
		{ $$ = $1; }
	| FUNC_CALL
		{ $$ = $1; }
	| lex_builtin
	  {
		yyerror("%s() is a built-in function, it cannot be redefined",
			tokstart);
		errcount++;
		/* yyerrok; */
	  }
	;

lex_builtin
	: LEX_BUILTIN
	| LEX_LENGTH
	;
		
function_prologue
	: LEX_FUNCTION 
		{
			param_counter = 0;
		}
	  func_name '(' opt_param_list r_paren opt_nls
		{
			$$ = append_right(make_param($3), $5);
			can_return = 1;
		}
	;

function_body
	: l_brace statements r_brace opt_semi
	  {
		$$ = $2;
		can_return = 0;
	  }
	;


pattern
	: exp
		{ $$ = $1; }
	| exp comma exp
		{ $$ = mkrangenode ( node($1, Node_cond_pair, $3) ); }
	;

regexp
	/*
	 * In this rule, want_regexp tells yylex that the next thing
	 * is a regexp so it should read up to the closing slash.
	 */
	: '/'
		{ ++want_regexp; }
	  REGEXP '/'
		{
		  NODE *n;
		  int len;

		  getnode(n);
		  n->type = Node_regex;
		  len = strlen($3);
		  n->re_exp = make_string($3, len);
		  n->re_reg = make_regexp($3, len, 0, 1);
		  n->re_text = NULL;
		  n->re_flags = CONST;
		  n->re_cnt = 1;
		  $$ = n;
		}
	;

action
	: l_brace statements r_brace opt_semi opt_nls
		{ $$ = $2 ; }
	| l_brace r_brace opt_semi opt_nls
		{ $$ = NULL; }
	;

statements
	: statement
		{ $$ = $1; }
	| statements statement
		{
			if ($1 == NULL || $1->type != Node_statement_list)
				$1 = node($1, Node_statement_list,(NODE *)NULL);
	    		$$ = append_right($1,
				node( $2, Node_statement_list, (NODE *)NULL));
	    		yyerrok;
		}
	| error
		{ $$ = NULL; }
	| statements error
		{ $$ = NULL; }
	;

statement_term
	: nls
	| semi opt_nls
	;

statement
	: semi opt_nls
		{ $$ = NULL; }
	| l_brace r_brace
		{ $$ = NULL; }
	| l_brace statements r_brace
		{ $$ = $2; }
	| if_statement
		{ $$ = $1; }
	| LEX_WHILE '(' exp r_paren opt_nls statement
		{ $$ = node ($3, Node_K_while, $6); }
	| LEX_DO opt_nls statement LEX_WHILE '(' exp r_paren opt_nls
		{ $$ = node ($6, Node_K_do, $3); }
	| LEX_FOR '(' NAME LEX_IN NAME r_paren opt_nls statement
	  {
		$$ = node ($8, Node_K_arrayfor, make_for_loop(variable($3,1),
			(NODE *)NULL, variable($5,1)));
	  }
	| LEX_FOR '(' opt_exp semi exp semi opt_exp r_paren opt_nls statement
	  {
		$$ = node($10, Node_K_for, (NODE *)make_for_loop($3, $5, $7));
	  }
	| LEX_FOR '(' opt_exp semi semi opt_exp r_paren opt_nls statement
	  {
		$$ = node ($9, Node_K_for,
			(NODE *)make_for_loop($3, (NODE *)NULL, $6));
	  }
	| LEX_BREAK statement_term
	   /* for break, maybe we'll have to remember where to break to */
		{ $$ = node ((NODE *)NULL, Node_K_break, (NODE *)NULL); }
	| LEX_CONTINUE statement_term
	   /* similarly */
		{ $$ = node ((NODE *)NULL, Node_K_continue, (NODE *)NULL); }
	| print '(' expression_list r_paren output_redir statement_term
		{ $$ = node ($3, $1, $5); }
	| print opt_rexpression_list output_redir statement_term
		{
			if ($1 == Node_K_print && $2 == NULL)
				$2 = node(node(make_number(0.0),
					       Node_field_spec,
					       (NODE *) NULL),
					  Node_expression_list,
					  (NODE *) NULL);

			$$ = node ($2, $1, $3);
		}
	| LEX_NEXT opt_exp statement_term
		{ NODETYPE type;

		  if ($2 && $2 == lookup("file")) {
			if (do_lint)
				warning("`next file' is a gawk extension");
			else if (do_unix || do_posix)
				yyerror("`next file' is a gawk extension");
			 else if (! io_allowed)
				yyerror("`next file' used in BEGIN or END action");
			type = Node_K_nextfile;
		  } else {
			if (! io_allowed)
				yyerror("next used in BEGIN or END action");
			type = Node_K_next;
		}
		  $$ = node ((NODE *)NULL, type, (NODE *)NULL);
		}
	| LEX_EXIT opt_exp statement_term
		{ $$ = node ($2, Node_K_exit, (NODE *)NULL); }
	| LEX_RETURN
		{ if (! can_return) yyerror("return used outside function context"); }
	  opt_exp statement_term
		{ $$ = node ($3, Node_K_return, (NODE *)NULL); }
	| LEX_DELETE NAME '[' expression_list ']' statement_term
		{ $$ = node (variable($2,1), Node_K_delete, $4); }
	| exp statement_term
		{ $$ = $1; }
	;

print
	: LEX_PRINT
		{ $$ = $1; }
	| LEX_PRINTF
		{ $$ = $1; }
	;

if_statement
	: LEX_IF '(' exp r_paren opt_nls statement
	  {
		$$ = node($3, Node_K_if, 
			node($6, Node_if_branches, (NODE *)NULL));
	  }
	| LEX_IF '(' exp r_paren opt_nls statement
	     LEX_ELSE opt_nls statement
		{ $$ = node ($3, Node_K_if,
				node ($6, Node_if_branches, $9)); }
	;

nls
	: NEWLINE
		{ want_assign = 0; }
	| nls NEWLINE
	;

opt_nls
	: /* empty */
	| nls
	;

input_redir
	: /* empty */
		{ $$ = NULL; }
	| '<' simp_exp
		{ $$ = node ($2, Node_redirect_input, (NODE *)NULL); }
	;

output_redir
	: /* empty */
		{ $$ = NULL; }
	| '>' exp
		{ $$ = node ($2, Node_redirect_output, (NODE *)NULL); }
	| APPEND_OP exp
		{ $$ = node ($2, Node_redirect_append, (NODE *)NULL); }
	| '|' exp
		{ $$ = node ($2, Node_redirect_pipe, (NODE *)NULL); }
	;

opt_param_list
	: /* empty */
		{ $$ = NULL; }
	| param_list
		{ $$ = $1; }
	;

param_list
	: NAME
		{ $$ = make_param($1); }
	| param_list comma NAME
		{ $$ = append_right($1, make_param($3)); yyerrok; }
	| error
		{ $$ = NULL; }
	| param_list error
		{ $$ = NULL; }
	| param_list comma error
		{ $$ = NULL; }
	;

/* optional expression, as in for loop */
opt_exp
	: /* empty */
		{ $$ = NULL; }
	| exp
		{ $$ = $1; }
	;

opt_rexpression_list
	: /* empty */
		{ $$ = NULL; }
	| rexpression_list
		{ $$ = $1; }
	;

rexpression_list
	: rexp
		{ $$ = node ($1, Node_expression_list, (NODE *)NULL); }
	| rexpression_list comma rexp
	  {
		$$ = append_right($1,
			node( $3, Node_expression_list, (NODE *)NULL));
		yyerrok;
	  }
	| error
		{ $$ = NULL; }
	| rexpression_list error
		{ $$ = NULL; }
	| rexpression_list error rexp
		{ $$ = NULL; }
	| rexpression_list comma error
		{ $$ = NULL; }
	;

opt_expression_list
	: /* empty */
		{ $$ = NULL; }
	| expression_list
		{ $$ = $1; }
	;

expression_list
	: exp
		{ $$ = node ($1, Node_expression_list, (NODE *)NULL); }
	| expression_list comma exp
		{
			$$ = append_right($1,
				node( $3, Node_expression_list, (NODE *)NULL));
			yyerrok;
		}
	| error
		{ $$ = NULL; }
	| expression_list error
		{ $$ = NULL; }
	| expression_list error exp
		{ $$ = NULL; }
	| expression_list comma error
		{ $$ = NULL; }
	;

/* Expressions, not including the comma operator.  */
exp	: variable ASSIGNOP 
		{ want_assign = 0; }
	  exp
		{
		  if (do_lint && $4->type == Node_regex)
			warning("Regular expression on left of assignment.");
		  $$ = node ($1, $2, $4);
		}
	| '(' expression_list r_paren LEX_IN NAME
		{ $$ = node (variable($5,1), Node_in_array, $2); }
	| exp '|' LEX_GETLINE opt_variable
		{
		  $$ = node ($4, Node_K_getline,
			 node ($1, Node_redirect_pipein, (NODE *)NULL));
		}
	| LEX_GETLINE opt_variable input_redir
		{
		  if (do_lint && ! io_allowed && $3 == NULL)
			warning("non-redirected getline undefined inside BEGIN or END action");
		  $$ = node ($2, Node_K_getline, $3);
		}
	| exp LEX_AND exp
		{ $$ = node ($1, Node_and, $3); }
	| exp LEX_OR exp
		{ $$ = node ($1, Node_or, $3); }
	| exp MATCHOP exp
		{
		  if ($1->type == Node_regex)
			warning("Regular expression on left of MATCH operator.");
		  $$ = node ($1, $2, mk_rexp($3));
		}
	| regexp
		{ $$ = $1; }
	| '!' regexp %prec UNARY
		{
		  $$ = node(node(make_number(0.0),
				 Node_field_spec,
				 (NODE *) NULL),
		            Node_nomatch,
			    $2);
		}
	| exp LEX_IN NAME
		{ $$ = node (variable($3,1), Node_in_array, $1); }
	| exp RELOP exp
		{
		  if (do_lint && $3->type == Node_regex)
			warning("Regular expression on left of comparison.");
		  $$ = node ($1, $2, $3);
		}
	| exp '<' exp
		{ $$ = node ($1, Node_less, $3); }
	| exp '>' exp
		{ $$ = node ($1, Node_greater, $3); }
	| exp '?' exp ':' exp
		{ $$ = node($1, Node_cond_exp, node($3, Node_if_branches, $5));}
	| simp_exp
		{ $$ = $1; }
	| exp simp_exp %prec CONCAT_OP
		{ $$ = node ($1, Node_concat, $2); }
	;

rexp