Celestin Apprentice 2/Apprentice-Release2.iso/Tools/MPW/gawk 2.11.1r3/Sources/awk.y

Text File | 1991-06-01 | 37.4 KB | 1,751 lines | [TEXT/MPS ]

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

/*
 * Copyright (C) 1986, 1988, 1989 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 1, 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, 675 Mass Ave, Cambridge, MA 02139, USA.
 */

/* 01Jun91    Matthias Neeracher    <[e-mail]>    MPW port */

%{
#ifdef DEBUG
#define YYDEBUG 12
#endif

#include "awk.h"
#ifdef macintosh
#include "StdLib.h"
#endif

/*
 * This line is necessary since the Bison parser skeleton uses bcopy.
 * Systems without memcpy should use -DMEMCPY_MISSING, per the Makefile.
 * It should not hurt anything if Yacc is being used instead of Bison.
 */
#define bcopy(s,d,n)    memcpy((d),(s),(n))

extern void msg();
extern struct re_pattern_buffer *mk_re_parse();

NODE *node();
NODE *lookup();
NODE *install();

static NODE *snode();
static NODE *mkrangenode();
static FILE *pathopen();
static NODE *make_for_loop();
static NODE *append_right();
static void func_install();
static NODE *make_param();
static int hashf();
static void pop_params();
static void pop_var();
static int yylex ();
#ifndef macintosh
static void yyerror();
#else
static void yyerror(char *, ...);
#endif

static int want_regexp;        /* lexical scanning kludge */
static int want_assign;        /* lexical scanning kludge */
static int can_return;        /* lexical scanning kludge */
static int io_allowed = 1;    /* lexical scanning kludge */
static int lineno = 1;        /* for error msgs */
static char *lexptr;        /* pointer to next char during parsing */
static char *lexptr_begin;    /* keep track of where we were for error msgs */
static int curinfile = -1;    /* index into sourcefiles[] */
static int param_counter;

NODE *variables[HASHSIZE];

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> 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> r_paren comma nls opt_nls print

%type <sval> func_name
%token <sval> FUNC_CALL NAME REGEXP
%token <lval> ERROR
%token <nodeval> NUMBER 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 <ptrval> 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 NUMBER
%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);
            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);
        $$ = NULL;
        io_allowed = 1;
        yyerrok;
        SpinMacCursor(-1);
      }
    | LEX_END { io_allowed = 0; }
      action
      {
        if (end_block) {
            if (end_block->type != Node_rule_list)
                end_block = node(end_block, Node_rule_list,
                    (NODE *)NULL);
            append_right (end_block, node(
                node((NODE *)NULL, Node_rule_node, $3),
                Node_rule_list, (NODE *)NULL));
        } else
            end_block = node((NODE *)NULL, Node_rule_node, $3);
        $$ = NULL;
        io_allowed = 1;
        yyerrok;
      }
    | LEX_BEGIN statement_term
      {
        msg ("error near line %d: BEGIN blocks must have an action part", lineno);
        errcount++;
        yyerrok;
      }
    | LEX_END statement_term
      {
        msg ("error near line %d: END blocks must have an action part", lineno);
        errcount++;
        yyerrok;
      }
    | pattern action
        { $$ = node ($1, Node_rule_node, $2); yyerrok; }
    | action
        { $$ = node ((NODE *)NULL, Node_rule_node, $1); yyerrok; }
    | pattern statement_term
        { if($1) $$ = node ($1, Node_rule_node, (NODE *)NULL); yyerrok; }
    | function_prologue function_body
        {
            func_install($1, $2);
            $$ = NULL;
            yyerrok;
        }
    ;

func_name
    : NAME
        { $$ = $1; }
    | FUNC_CALL
        { $$ = $1; }
    ;

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
      {
        $$ = $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 '/'
        {
          want_regexp = 0;
          $$ = node((NODE *)NULL,Node_regex,(NODE *)mk_re_parse($3, 0));
          $$ -> re_case = 0;
          emalloc ($$ -> re_text, char *, strlen($3)+1, "regexp");
          strcpy ($$ -> re_text, $3);
        }
    ;

action
    : l_brace r_brace opt_semi
        {
            /* empty actions are different from missing actions */
            $$ = node ((NODE *) NULL, Node_illegal, (NODE *) NULL);
        }
    | l_brace statements r_brace opt_semi
        { $$ = $2 ; }
    ;

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
        { $<nodetypeval>$ = Node_illegal; }
    | semi opt_nls
        { $<nodetypeval>$ = Node_illegal; }
    ;


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
      {
        $$ = node ($8, Node_K_arrayfor, make_for_loop(variable($3),
            (NODE *)NULL, variable($5)));
      }
    | LEX_FOR '(' opt_exp semi exp semi opt_exp r_paren opt_nls statement
      {
        $$ = 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
        { $$ = node ($2, $1, $3); }
    | LEX_NEXT
        { if (! io_allowed) yyerror("next used in BEGIN or END action"); }
      statement_term
        { $$ = node ((NODE *)NULL, Node_K_next, (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
        { $$ = node (variable($2), Node_K_delete, $4); }
    | exp statement_term
        { $$ = $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
        { $<nodetypeval>$ = NULL; }
    | nls NEWLINE
        { $<nodetypeval>$ = NULL; }
    ;

opt_nls
    : /* empty */
        { $<nodetypeval>$ = NULL; }
    | nls
        { $<nodetypeval>$ = NULL; }
    ;

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
        { $$ = node ($1, $2, $4); }
    | '(' expression_list r_paren LEX_IN NAME
        { $$ = node (variable($5), Node_in_array, $2); }
    | exp '|' LEX_GETLINE opt_variable
        {
          $$ = node ($4, Node_K_getline,
             node ($1, Node_redirect_pipein, (NODE *)NULL));
        }
    | LEX_GETLINE opt_variable input_redir
        {
          /* "too painful to do right" */
          /*
          if (! io_allowed && $3 == NULL)
            yyerror("non-redirected getline illegal inside BEGIN or END action");
          */
          $$ = 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
         { $$ = node ($1, $2, $3); }
    | regexp
        { $$ = $1; }
    | '!' regexp %prec UNARY
        { $$ = node((NODE *) NULL, Node_nomatch, $2); }
    | exp LEX_IN NAME
        { $$ = node (variable($3), Node_in_array, $1); }
    | exp RELOP exp
        { $$ = node ($1, $2, $3); }
    | exp '<' exp
        { $$ = 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
        { $$ = $1; }
    | exp exp %prec CONCAT_OP
        { $$ = node ($1, Node_concat, $2); }
    ;

rexp
    : variable ASSIGNOP
        { want_assign = 0; }
        rexp
        { $$ = node ($1, $2, $4); }
    | rexp LEX_AND rexp
        { $$ = node ($1, Node_and, $3); }
    | rexp LEX_OR rexp
        { $$ = node ($1, Node_or, $3); }
    | LEX_GETLINE opt_variable input_redir
        {
          /* "too painful to do right" */
          /*
          if (! io_allowed && $3 == NULL)
            yyerror("non-redirected getline illegal inside BEGIN or END action");
          */
          $$ = node ($2, Node_K_getline, $3);
        }
    | regexp
        { $$ = $1; }
    | '!' regexp %prec UNARY
        { $$ = node((NODE *) NULL, Node_nomatch, $2); }
    | rexp MATCHOP rexp
         { $$ = node ($1, $2, $3); }
    | rexp LEX_IN NAME
        { $$ = node (variable($3), Node_in_array, $1); }
    | rexp RELOP rexp
        { $$ = node ($1, $2, $3); }
    | rexp '?' rexp ':' rexp
        { $$ = node($1, Node_cond_exp, node($3, Node_if_branches, $5));}
    | simp_exp
        { $$ = $1; }
    | rexp rexp %prec CONCAT_OP
        { $$ = node ($1, Node_concat, $2); }
    ;

simp_exp
    : '!' simp_exp %prec UNARY
        { $$ = node ($2, Node_not,(NODE *) NULL); }
    | '(' exp r_paren
        { $$ = $2; }
    | LEX_BUILTIN '(' opt_expression_list r_paren
        { $$ = snode ($3, Node_builtin, $1); }
    | LEX_LENGTH '(' opt_expression_list r_paren
        { $$ = snode ($3, Node_builtin, $1); }
    | LEX_LENGTH
        { $$ = snode ((NODE *)NULL, Node_builtin, $1); }
    | FUNC_CALL '(' opt_expression_list r_paren
      {
        $$ = node ($3, Node_func_call, make_string($1, strlen($1)));
      }
    | INCREMENT variable
        { $$ = node ($2, Node_preincrement, (NODE *)NULL); }
    | DECREMENT variable
        { $$ = node ($2, Node_predecrement, (NODE *)NULL); }
    | variable INCREMENT
        { $$ = node ($1, Node_postincrement, (NODE *)NULL); }
    | variable DECREMENT
        { $$ = node ($1, Node_postdecrement, (NODE *)NULL); }
    | variable
        { $$ = $1; }
    | NUMBER
        { $$ = $1; }
    | YSTRING
        { $$ = $1; }

    /* Binary operators in order of decreasing precedence.  */
    | simp_exp '^' simp_exp
        { $$ = node ($1, Node_exp, $3); }
    | simp_exp '*' simp_exp
        { $$ = node ($1, Node_times, $3); }
    | simp_exp '/' simp_exp
        { $$ = node ($1, Node_quotient, $3); }
    | simp_exp '%' simp_exp
        { $$ = node ($1, Node_mod, $3); }
    | simp_exp '+' simp_exp
        { $$ = node ($1, Node_plus, $3); }
    | simp_exp '-' simp_exp
        { $$ = node ($1, Node_minus, $3); }
    | '-' simp_exp    %prec UNARY
        { $$ = node ($2, Node_unary_minus, (NODE *)NULL); }
    | '+' simp_exp    %prec UNARY
        { $$ = $2; }
    ;

opt_variable
    : /* empty */
        { $$ = NULL; }
    | variable
        { $$ = $1; }
    ;

variable
    : NAME
        { want_assign = 1; $$ = variable ($1); }
    | NAME '[' expression_list ']'
        { want_assign = 1; $$ = node (variable($1), Node_subscript, $3); }
    | '$' simp_exp
        { want_assign = 1; $$ = node ($2, Node_field_spec, (NODE *)NULL); }
    ;

l_brace
    : '{' opt_nls
    ;

r_brace
    : '}' opt_nls    { yyerrok; }
    ;

r_paren
    : ')' { $<nodetypeval>$ = Node_illegal; yyerrok; }
    ;

opt_semi
    : /* empty */
    | semi
    ;

semi
    : ';'    { yyerrok; }
    ;

comma    : ',' opt_nls    { $<nodetypeval>$ = Node_illegal; yyerrok; }
    ;

%%

struct token {
    char *operator;        /* text to match */
    NODETYPE value;        /* node type */
    int class;        /* lexical class */
    short nostrict;        /* ignore if in strict compatibility mode */
    NODE *(*ptr) ();    /* function that implements this keyword */
};

extern NODE
    *do_exp(),    *do_getline(),    *do_index(),    *do_length(),
    *do_sqrt(),    *do_log(),    *do_sprintf(),    *do_substr(),
    *do_split(),    *do_system(),    *do_int(),    *do_close(),
    *do_atan2(),    *do_sin(),    *do_cos(),    *do_rand(),
    *do_srand(),    *do_match(),    *do_tolower(),    *do_toupper(),
    *do_sub(),    *do_gsub();

/* Special functions for debugging */
#ifdef DEBUG
NODE *do_prvars(), *do_bp();
#endif

/* Tokentab is sorted ascii ascending order, so it can be binary searched. */

static struct token tokentab[] = {
    { "BEGIN",    Node_illegal,        LEX_BEGIN,    0,    0 },
    { "END",    Node_illegal,        LEX_END,    0,    0 },
    { "atan2",    Node_builtin,        LEX_BUILTIN,    0,    do_atan2 },
#ifdef DEBUG
    { "bp",        Node_builtin,        LEX_BUILTIN,    0,    do_bp },
#endif
    { "break",    Node_K_break,        LEX_BREAK,    0,    0 },
    { "close",    Node_builtin,        LEX_BUILTIN,    0,    do_close },
    { "continue",    Node_K_continue,    LEX_CONTINUE,    0,    0 },
    { "cos",    Node_builtin,        LEX_BUILTIN,    0,    do_cos },
    { "delete",    Node_K_delete,        LEX_DELETE,    0,    0 },
    { "do",        Node_K_do,        LEX_DO,        0,    0 },
    { "else",    Node_illegal,        LEX_ELSE,    0,    0 },
    { "exit",    Node_K_exit,        LEX_EXIT,    0,    0 },
    { "exp",    Node_builtin,        LEX_BUILTIN,    0,    do_exp },
    { "for",    Node_K_for,        LEX_FOR,    0,    0 },
    { "func",    Node_K_function,    LEX_FUNCTION,    0,    0 },
    { "function",    Node_K_function,    LEX_FUNCTION,    0,    0 },
    { "getline",    Node_K_getline,        LEX_GETLINE,    0,    0 },
    { "gsub",    Node_builtin,        LEX_BUILTIN,    0,    do_gsub },
    { "if",        Node_K_if,        LEX_IF,        0,    0 },
    { "in",        Node_illegal,        LEX_IN,        0,    0 },
    { "index",    Node_builtin,        LEX_BUILTIN,    0,    do_index },
    { "int",    Node_builtin,        LEX_BUILTIN,    0,    do_int },
    { "length",    Node_builtin,        LEX_LENGTH,    0,    do_length },
    { "log",    Node_builtin,        LEX_BUILTIN,    0,    do_log },
    { "match",    Node_builtin,        LEX_BUILTIN,    0,    do_match },
    { "next",    Node_K_next,        LEX_NEXT,    0,    0 },
    { "print",    Node_K_print,        LEX_PRINT,    0,    0 },
    { "printf",    Node_K_printf,        LEX_PRINTF,    0,    0 },
#ifdef DEBUG
    { "prvars",    Node_builtin,        LEX_BUILTIN,    0,    do_prvars },
#endif
    { "rand",    Node_builtin,        LEX_BUILTIN,    0,    do_rand },
    { "return",    Node_K_return,        LEX_RETURN,    0,    0 },
    { "sin",    Node_builtin,        LEX_BUILTIN,    0,    do_sin },
    { "split",    Node_builtin,        LEX_BUILTIN,    0,    do_split },
    { "sprintf",    Node_builtin,        LEX_BUILTIN,    0,    do_sprintf },
    { "sqrt",    Node_builtin,        LEX_BUILTIN,    0,    do_sqrt },
    { "srand",    Node_builtin,        LEX_BUILTIN,    0,    do_srand },
    { "sub",    Node_builtin,        LEX_BUILTIN,    0,    do_sub },
    { "substr",    Node_builtin,        LEX_BUILTIN,    0,    do_substr },
    { "system",    Node_builtin,        LEX_BUILTIN,    0,    do_system },
    { "tolower",    Node_builtin,        LEX_BUILTIN,    0,    do_tolower },
    { "toupper",    Node_builtin,        LEX_BUILTIN,    0,    do_toupper },
    { "while",    Node_K_while,        LEX_WHILE,    0,    0 },
};

static char *token_start;

/* VARARGS0 */
static void
#ifndef macintosh
yyerror(va_alist)
va_dcl
{
    char *mesg;
#else
yyerror(char *mesg, ...)
{
#endif
    va_list args;
    register char *ptr, *beg;
    char *scan;
#ifdef macintosh
    extern char **sourcefile;
    extern int tempsource, numfiles;
#endif

    errcount++;
#ifndef macintosh
    va_start(args);
    mesg = va_arg(args, char *);
    va_end(args);
#else
    va_start(args, mesg);
    va_end(args);
#endif
    /* Find the current line in the input file */
    if (! lexptr) {
        beg = "(END OF FILE)";
        ptr = beg + 13;
    } else {
        if (*lexptr == '\n' && lexptr != lexptr_begin)
            --lexptr;
        for (beg = lexptr; beg != lexptr_begin && *beg != '\n'; --beg)
            ;
        /* NL isn't guaranteed */
        for (ptr = lexptr; *ptr && *ptr != '\n'; ptr++)
            ;
        if (beg != lexptr_begin)
            beg++;
    }
#ifdef macintosh
    msg("# %.*s", ptr - beg, beg);
    putc('#', stderr);
    putc(' ', stderr);
    scan = beg;
    while (scan < token_start)
        if (*scan++ == '\t')
            putc('\t', stderr);
        else
            putc(' ', stderr);
    putc('^', stderr);
    putc(' ', stderr);
    vfprintf(stderr, mesg, args);
    putc('\n', stderr);
    if (!tempsource || numfiles)
        msg("File '%s'; Line %d\n", sourcefile[curinfile], lineno);
    else
        msg("# Syntax error near line %d:\n", lineno);
#else
    msg("syntax error near line %d:\n%.*s", lineno, ptr - beg, beg);
    scan = beg;
    while (scan < token_start)
        if (*scan++ == '\t')
            putc('\t', stderr);
        else
            putc(' ', stderr);
    putc('^', stderr);
    putc(' ', stderr);
    vfprintf(stderr, mesg, args);
    putc('\n', stderr);
#endif
    exit(1);
}

/*
 * Parse a C escape sequence.  STRING_PTR points to a variable containing a
 * pointer to the string to parse.  That pointer is updated past the
 * characters we use.  The value of the escape sequence is returned.
 *
 * A negative value means the sequence \ newline was seen, which is supposed to
 * be equivalent to nothing at all.
 *
 * If \ is followed by a null character, we return a negative value and leave
 * the string pointer pointing at the null character.
 *
 * If \ is followed by 000, we return 0 and leave the string pointer after the
 * zeros.  A value of 0 does not mean end of string.
 */

int
parse_escape(string_ptr)
char **string_ptr;
{
    register int c = *(*string_ptr)++;
    register int i;
    register int count;

    switch (c) {
    case 'a':
        return BELL;
    case 'b':
        return '\b';
    case 'f':
        return '\f';
    case 'n':
        return '\n';
    case 'r':
        return '\r';
    case 't':
        return '\t';
    case 'v':
        return '\v';
    case '\n':
        return -2;
    case 0:
        (*string_ptr)--;
        return -1;
    case '0':
    case '1':
    case '2':
    case '3':
    case '4':
    case '5':
    case '6':
    case '7':
        i = c - '0';
        count = 0;
        while (++count < 3) {
            if ((c = *(*string_ptr)++) >= '0' && c <= '7') {
                i *= 8;
                i += c - '0';
            } else {
                (*string_ptr)--;
                break;
            }
        }
        return i;
    case 'x':
        i = 0;
        while (1) {
            if (isxdigit((c = *(*string_ptr)++))) {
                if (isdigit(c))
                    i += c - '0';
                else if (isupper(c))
                    i += c - 'A' + 10;
                else
                    i += c - 'a' + 10;
            } else {
                (*string_ptr)--;
                break;
            }
        }
        return i;
    default:
        return c;
    }
}

/*
 * Read the input and turn it into tokens. Input is now read from a file
 * instead of from malloc'ed memory. The main program takes a program
 * passed as a command line argument and writes it to a temp file. Otherwise
 * the file name is made available in an external variable.
 */

static int
yylex()
{
    register int c;
    register int namelen;
    register char *tokstart;
    char *tokkey;
    static did_newline = 0;    /* the grammar insists that actions end
                 * with newlines.  This was easier than
                 * hacking the grammar. */
    int seen_e = 0;        /* These are for numbers */
    int seen_point = 0;
    int esc_seen;
    extern char **sourcefile;
    extern int tempsource, numfiles;
    static int file_opened = 0;
    static FILE *fin;
    static char cbuf[BUFSIZ];
    int low, mid, high;
#ifdef DEBUG
    extern int debugging;
#endif

    if (! file_opened) {
        file_opened = 1;
#ifdef DEBUG
        if (debugging) {
            int i;

            for (i = 0; i <= numfiles; i++)
                fprintf (stderr, "sourcefile[%d] = %s\n", i,
                        sourcefile[i]);
        }
#endif
    nextfile:
        if ((fin = pathopen (sourcefile[++curinfile])) == NULL)
            fatal("cannot open `%s' for reading (%s)",
                sourcefile[curinfile],
                strerror(errno));
        *(lexptr = cbuf) = '\0';
        /*
         * immediately unlink the tempfile so that it will
         * go away cleanly if we bomb.
         * This unfortunately won't work on a Macintosh
         */
#ifndef macintosh
        if (tempsource && curinfile == 0)
            (void) unlink (sourcefile[curinfile]);
#endif
    }

retry:
    if (! *lexptr)
        if (fgets (cbuf, sizeof cbuf, fin) == NULL) {
            if (fin != NULL)
                fclose (fin);    /* be neat and clean */
#ifdef macintosh
            if (tempsource && curinfile == 0)
                (void) unlink (sourcefile[curinfile]);
#endif
            if (curinfile < numfiles)
                goto nextfile;
            return 0;
        } else
            lexptr = lexptr_begin = cbuf;

    if (want_regexp) {
        int in_brack = 0;

        want_regexp = 0;
        token_start = tokstart = lexptr;
        while (c = *lexptr++) {
            switch (c) {
            case '[':
                in_brack = 1;
                break;
            case ']':
                in_brack = 0;
                break;
            case '\\':
                if (*lexptr++ == '\0') {
                    yyerror("unterminated regexp ends with \\");
                    return ERROR;
                } else if (lexptr[-1] == '\n')
                    goto retry;
                break;
            case '/':    /* end of the regexp */
                if (in_brack)
                    break;

                lexptr--;
                yylval.sval = tokstart;
                return REGEXP;
            case '\n':
                lineno++;
            case '\0':
                lexptr--;    /* so error messages work */
                yyerror("unterminated regexp");
                return ERROR;
            }
        }
    }

    if (*lexptr == '\n') {
        lexptr++;
        lineno++;
        return NEWLINE;
    }

    while (*lexptr == ' ' || *lexptr == '\t')
        lexptr++;

    token_start = tokstart = lexptr;

    switch (c = *lexptr++) {
    case 0:
        return 0;

    case '\n':
        lineno++;
        return NEWLINE;

    case '#':        /* it's a comment */
        while (*lexptr != '\n' && *lexptr != '\0')
            lexptr++;
        goto retry;

    case '\\':
        if (*lexptr == '\n') {
            lineno++;
            lexptr++;
            goto retry;
        } else
            break;
    case ')':
    case ']':
    case '(':
    case '[':
    case '$':
    case ';':
    case ':':
    case '?':

        /*
         * set node type to ILLEGAL because the action should set it
         * to the right thing
         */
        yylval.nodetypeval = Node_illegal;
        return c;

    case '{':
    case ',':
        yylval.nodetypeval = Node_illegal;
        return c;

    case '*':
        if (*lexptr == '=') {
            yylval.nodetypeval = Node_assign_times;
            lexptr++;
            return ASSIGNOP;
        } else if (*lexptr == '*') {    /* make ** and **= aliases
                         * for ^ and ^= */
            if (lexptr[1] == '=') {
                yylval.nodetypeval = Node_assign_exp;
                lexptr += 2;
                return ASSIGNOP;
            } else {
                yylval.nodetypeval = Node_illegal;
                lexptr++;
                return '^';
            }
        }
        yylval.nodetypeval = Node_illegal;
        return c;

    case '/':
        if (want_assign && *lexptr == '=') {
            yylval.nodetypeval = Node_assign_quotient;
            lexptr++;
            return ASSIGNOP;
        }
        yylval.nodetypeval = Node_illegal;
        return c;

    case '%':
        if (*lexptr == '=') {
            yylval.nodetypeval = Node_assign_mod;
            lexptr++;
            return ASSIGNOP;
        }
        yylval.nodetypeval = Node_illegal;
        return c;

    case '^':
        if (*lexptr == '=') {
            yylval.nodetypeval = Node_assign_exp;
            lexptr++;
            return ASSIGNOP;
        }
        yylval.nodetypeval = Node_illegal;
        return c;

    case '+':
        if (*lexptr == '=') {
            yylval.nodetypeval = Node_assign_plus;
            lexptr++;
            return ASSIGNOP;
        }
        if (*lexptr == '+') {
            yylval.nodetypeval = Node_illegal;
            lexptr++;
            return INCREMENT;
        }
        yylval.nodetypeval = Node_illegal;
        return c;

    case '!':
        if (*lexptr == '=') {
            yylval.nodetypeval = Node_notequal;
            lexptr++;
            return RELOP;
        }
        if (*lexptr == '~') {
            yylval.nodetypeval = Node_nomatch;
            lexptr++;
            return MATCHOP;
        }
        yylval.nodetypeval = Node_illegal;
        return c;

    case '<':
        if (*lexptr == '=') {
            yylval.nodetypeval = Node_leq;
            lexptr++;
            return RELOP;
        }
        yylval.nodetypeval = Node_less;
        return c;

    case '=':
        if (*lexptr == '=') {
            yylval.nodetypeval = Node_equal;
            lexptr++;
            return RELOP;
        }
        yylval.nodetypeval = Node_assign;
        return ASSIGNOP;

    case '>':
        if (*lexptr == '=') {
            yylval.nodetypeval = Node_geq;
            lexptr++;
            return RELOP;
        } else if (*lexptr == '>') {
            yylval.nodetypeval = Node_redirect_append;
            lexptr++;
            return APPEND_OP;
        }
        yylval.nodetypeval = Node_greater;
        return c;

    case '~':
        yylval.nodetypeval = Node_match;
        return MATCHOP;

    case '}':
        /*
         * Added did newline stuff.  Easier than
         * hacking the grammar
         */
        if (did_newline) {
            did_newline = 0;
            return c;
        }
        did_newline++;
        --lexptr;
        return NEWLINE;

    case '"':
        esc_seen = 0;
        while (*lexptr != '\0') {
            switch (*lexptr++) {
            case '\\':
                esc_seen = 1;
                if (*lexptr == '\n')
                    yyerror("newline in string");
                if (*lexptr++ != '\0')
                    break;
                /* fall through */
            case '\n':
                lexptr--;
                yyerror("unterminated string");
                return ERROR;
            case '"':
                yylval.nodeval = make_str_node(tokstart + 1,
                        lexptr-tokstart-2, esc_seen);
                yylval.nodeval->flags |= PERM;
                return YSTRING;
            }
        }
        return ERROR;

    case '-':
        if (*lexptr == '=') {
            yylval.nodetypeval = Node_assign_minus;
            lexptr++;
            return ASSIGNOP;
        }
        if (*lexptr == '-') {
            yylval.nodetypeval = Node_illegal;
            lexptr++;
            return DECREMENT;
        }
        yylval.nodetypeval = Node_illegal;
        return c;

    case '0':
    case '1':
    case '2':
    case '3':
    case '4':
    case '5':
    case '6':
    case '7':
    case '8':
    case '9':
    case '.':
        /* It's a number */
        for (namelen = 0; (c = tokstart[namelen]) != '\0'; namelen++) {
            switch (c) {
            case '.':
                if (seen_point)
                    goto got_number;
                ++seen_point;
                break;
            case 'e':
            case 'E':
                if (seen_e)
                    goto got_number;
                ++seen_e;
                if (tokstart[namelen + 1] == '-' ||
                    tokstart[namelen + 1] == '+')
                    namelen++;
                break;
            case '0':
            case '1':
            case '2':
            case '3':
            case '4':
            case '5':
            case '6':
            case '7':
            case '8':
            case '9':
                break;
            default:
                goto got_number;
            }
        }

got_number:
        lexptr = tokstart + namelen;
        /*
        yylval.nodeval = make_string(tokstart, namelen);
        (void) force_number(yylval.nodeval);
        */
        yylval.nodeval = make_number(atof(tokstart));
        yylval.nodeval->flags |= PERM;
        return NUMBER;

    case '&':
        if (*lexptr == '&') {
            yylval.nodetypeval = Node_and;
            while (c = *++lexptr) {
                if (c == '#')
                    while ((c = *++lexptr) != '\n'
                           && c != '\0')
                        ;
                if (c == '\n')
                    lineno++;
                else if (! isspace(c))
                    break;
            }
            return LEX_AND;
        }
        return ERROR;

    case '|':
        if (*lexptr == '|') {
            yylval.nodetypeval = Node_or;
            while (c = *++lexptr) {
                if (c == '#')
                    while ((c = *++lexptr) != '\n'
                           && c != '\0')
                        ;
                if (c == '\n')
                    lineno++;
                else if (! isspace(c))
                    break;
            }
            return LEX_OR;
        }
        yylval.nodetypeval = Node_illegal;
        return c;
    }

    if (c != '_' && ! isalpha(c)) {
        yyerror("Invalid char '%c' in expression\n", c);
        return ERROR;
    }

    /* it's some type of name-type-thing.  Find its length */
    for (namelen = 0; is_identchar(tokstart[namelen]); namelen++)
        /* null */ ;
    emalloc(tokkey, char *, namelen+1, "yylex");
    memcpy(tokkey, tokstart, namelen);
    tokkey[namelen] = '\0';

    /* See if it is a special token.  */
    low = 0;
    high = (sizeof (tokentab) / sizeof (tokentab[0])) - 1;
    while (low <= high) {
        int i, c;

        mid = (low + high) / 2;
        c = *tokstart - tokentab[mid].operator[0];
        i = c ? c : strcmp (tokkey, tokentab[mid].operator);

        if (i < 0) {        /* token < mid */
            high = mid - 1;
        } else if (i > 0) {    /* token > mid */
            low = mid + 1;
        } else {
            lexptr = tokstart + namelen;
            if (strict && tokentab[mid].nostrict)
                break;
            if (tokentab[mid].class == LEX_BUILTIN
                || tokentab[mid].class == LEX_LENGTH)
                yylval.ptrval = tokentab[mid].ptr;
            else
                yylval.nodetypeval = tokentab[mid].value;
            return tokentab[mid].class;
        }
    }

    /* It's a name.  See how long it is.  */
    yylval.sval = tokkey;
    lexptr = tokstart + namelen;
    if (*lexptr == '(')
        return FUNC_CALL;
    else
        return NAME;
}

#ifndef DEFPATH
#ifdef MSDOS
#define DEFPATH    "."
#define ENVSEP    ';'
#else
#ifdef macintosh
#define DEFPATH    ":"
#define ENVSEP    ','
#else
#define DEFPATH    ".:/usr/lib/awk:/usr/local/lib/awk"
#define ENVSEP    ':'
#endif
#endif
#endif

static FILE *
pathopen (file)
char *file;
{
    static char *savepath = DEFPATH;
    static int first = 1;
    char *awkpath, *cp;
    char trypath[BUFSIZ];
    FILE *fp;
#ifdef DEBUG
    extern int debugging;
#endif
    int fd;

    if (strcmp (file, "-") == 0)
        return (stdin);

    if (strict)
        return (fopen (file, "r"));

    if (first) {
        first = 0;
        if ((awkpath = getenv ("AWKPATH")) != NULL && *awkpath)
            savepath = awkpath;    /* used for restarting */
    }
    awkpath = savepath;

    /* some kind of path name, no search */
#ifndef MSDOS
    if (strchr (file, '/') != NULL)
#else
#ifdef macintosh
    if (strchr (file, ':') != NULL)
#else
    if (strchr (file, '/') != NULL || strchr (file, '\\') != NULL
            || strchr (file, ':') != NULL)
#endif
#endif
        return ( (fd = devopen (file, "r")) >= 0 ?
                fdopen(fd, "r") :
                NULL);

    do {
        trypath[0] = '\0';
        /* this should take into account limits on size of trypath */
        for (cp = trypath; *awkpath && *awkpath != ENVSEP; )
            *cp++ = *awkpath++;

        if (cp != trypath) {    /* nun-null element in path */
#ifndef macintosh
            *cp++ = '/';
#else
            *cp++ = ':';
#endif
            strcpy (cp, file);
        } else
            strcpy (trypath, file);
#ifdef DEBUG
        if (debugging)
            fprintf(stderr, "trying: %s\n", trypath);
#endif
        if ((fd = devopen (trypath, "r")) >= 0
            && (fp = fdopen(fd, "r")) != NULL)
            return (fp);

        /* no luck, keep going */
        if(*awkpath == ENVSEP && awkpath[1] != '\0')
            awkpath++;    /* skip colon */
    } while (*awkpath);
#if defined(MSDOS) || defined(macintosh)
    /*
     * Under DOS (and probably elsewhere) you might have one of the awk
     * paths defined, WITHOUT the current working directory in it.
     * Therefore you should try to open the file in the current directory.
     */
    return ( (fd = devopen(file, "r")) >= 0 ? fdopen(fd, "r") : NULL);
#else
    return (NULL);
#endif
}

static NODE *
node_common(op)
NODETYPE op;
{
    register NODE *r;
    extern int numfiles;
    extern int tempsource;
    extern char **sourcefile;

    r = newnode(op);
    r->source_line = lineno;
    if (numfiles > -1 && ! tempsource)
        r->source_file = sourcefile[curinfile];
    else
        r->source_file = NULL;
    return r;
}

/*
 * This allocates a node with defined lnode and rnode.
 * This should only be used by yyparse+co while reading in the program
 */
NODE *
node(left, op, right)
NODE *left, *right;
NODETYPE op;
{
    register NODE *r;

    r = node_common(op);
    r->lnode = left;
    r->rnode = right;
    return r;
}

/*
 * This allocates a node with defined subnode and proc
 * Otherwise like node()
 */
static NODE *
snode(subn, op, procp)
NODETYPE op;
NODE *(*procp) ();
NODE *subn;
{
    register NODE *r;

    r = node_common(op);
    r->subnode = subn;
    r->proc = procp;
    return r;
}

/*
 * This allocates a Node_line_range node with defined condpair and
 * zeroes the trigger word to avoid the temptation of assuming that calling
 * 'node( foo, Node_line_range, 0)' will properly initialize 'triggered'.
 */
/* Otherwise like node() */
static NODE *
mkrangenode(cpair)
NODE *cpair;
{
    register NODE *r;

    r = newnode(Node_line_range);
    r->condpair = cpair;
    r->triggered = 0;
    return r;
}

/* Build a for loop */
static NODE *
make_for_loop(init, cond, incr)
NODE *init, *cond, *incr;
{
    register FOR_LOOP_HEADER *r;
    NODE *n;

    emalloc(r, FOR_LOOP_HEADER *, sizeof(FOR_LOOP_HEADER), "make_for_loop");
    n = newnode(Node_illegal);
    r->init = init;
    r->cond = cond;
    r->incr = incr;
    n->sub.nodep.r.hd = r;
    return n;
}

/*
 * Install a name in the hash table specified, even if it is already there.
 * Name stops with first non alphanumeric. Caller must check against
 * redefinition if that is desired.
 */
NODE *
install(table, name, value)
NODE **table;
char *name;
NODE *value;
{
    register NODE *hp;
    register int len, bucket;
    register char *p;

    len = 0;
    p = name;
    while (is_identchar(*p))
        p++;
    len = p - name;

    hp = newnode(Node_hashnode);
    bucket = hashf(name, len, HASHSIZE);
    hp->hnext = table[bucket];
    table[bucket] = hp;
    hp->hlength = len;
    hp->hvalue = value;
    emalloc(hp->hname, char *, len + 1, "install");
    memcpy(hp->hname, name, len);
    hp->hname[len] = '\0';
    return hp->hvalue;
}

/*
 * find the most recent hash node for name name (ending with first
 * non-identifier char) installed by install
 */
NODE *
lookup(table, name)
NODE **table;
char *name;
{
    register char *bp;
    register NODE *bucket;
    register int len;

    for (bp = name; is_identchar(*bp); bp++)
        ;
    len = bp - name;
    bucket = table[hashf(name, len, HASHSIZE)];
    while (bucket) {
        if (bucket->hlength == len && STREQN(bucket->hname, name, len))
            return bucket->hvalue;
        bucket = bucket->hnext;
    }
    return NULL;
}

#define HASHSTEP(old, c) ((old << 1) + c)
#define MAKE_POS(v) (v & ~0x80000000)    /* make number positive */

/*
 * return hash function on name.
 */
static int
hashf(name, len, hashsize)
register char *name;
register int len;
int hashsize;
{
    register int r = 0;

    while (len--)
        r = HASHSTEP(r, *name++);

    r = MAKE_POS(r) % hashsize;
    return r;
}

/*
 * Add new to the rightmost branch of LIST.  This uses n^2 time, so we make
 * a simple attempt at optimizing it.
 */
static NODE *
append_right(list, new)
NODE *list, *new;

{
    register NODE *oldlist;
    static NODE *savefront = NULL, *savetail = NULL;

    oldlist = list;
    if (savefront == oldlist) {
        savetail = savetail->rnode = new;
        return oldlist;
    } else
        savefront = oldlist;
    while (list->rnode != NULL)
        list = list->rnode;
    savetail = list->rnode = new;
    return oldlist;
}

/*
 * check if name is already installed;  if so, it had better have Null value,
 * in which case def is added as the value. Otherwise, install name with def
 * as value.
 */
static void
func_install(params, def)
NODE *params;
NODE *def;
{
    NODE *r;

    pop_params(params->rnode);
    pop_var(params, 0);
    r = lookup(variables, params->param);
    if (r != NULL) {
        fatal("function name `%s' previously defined", params->param);
    } else
        (void) install(variables, params->param,
            node(params, Node_func, def));
}

static void
pop_var(np, freeit)
NODE *np;
int freeit;
{
    register char *bp;
    register NODE *bucket, **save;
    register int len;
    char *name;

    name = np->param;
    for (bp = name; is_identchar(*bp); bp++)
        ;
    len = bp - name;
    save = &(variables[hashf(name, len, HASHSIZE)]);
    for (bucket = *save; bucket; bucket = bucket->hnext) {
        if (len == bucket->hlength && STREQN(bucket->hname, name, len)) {
            *save = bucket->hnext;
            freenode(bucket);
            free(bucket->hname);
            if (freeit)
                free(np->param);
            return;
        }
        save = &(bucket->hnext);
    }
}

static void
pop_params(params)
NODE *params;
{
    register NODE *np;

    for (np = params; np != NULL; np = np->rnode)
        pop_var(np, 1);
}

static NODE *
make_param(name)
char *name;
{
    NODE *r;

    r = newnode(Node_param_list);
    r->param = name;
    r->rnode = NULL;
    r->param_cnt = param_counter++;
    return (install(variables, name, r));
}

/* Name points to a variable name.  Make sure its in the symbol table */
NODE *
variable(name)
char *name;
{
    register NODE *r;

    if ((r = lookup(variables, name)) == NULL)
        r = install(variables, name,
            node(Nnull_string, Node_var, (NODE *) NULL));
    return r;
}