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Diffstat (limited to 'contrib/gcc/cexp.y')
| -rw-r--r-- | contrib/gcc/cexp.y | 1047 |
1 files changed, 1047 insertions, 0 deletions
diff --git a/contrib/gcc/cexp.y b/contrib/gcc/cexp.y new file mode 100644 index 0000000..d83de80 --- /dev/null +++ b/contrib/gcc/cexp.y @@ -0,0 +1,1047 @@ +/* Parse C expressions for CCCP. + Copyright (C) 1987, 1992, 1994, 1995 Free Software Foundation. + +This program 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, or (at your option) any +later version. + +This program 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 this program; if not, write to the Free Software +Foundation, 59 Temple Place - Suite 330, +Boston, MA 02111-1307, USA. + + In other words, you are welcome to use, share and improve this program. + You are forbidden to forbid anyone else to use, share and improve + what you give them. Help stamp out software-hoarding! + + Adapted from expread.y of GDB by Paul Rubin, July 1986. */ + +/* Parse a C expression from text in a string */ + +%{ +#include "config.h" +#include <setjmp.h> +/* #define YYDEBUG 1 */ + +#ifdef MULTIBYTE_CHARS +#include <stdlib.h> +#include <locale.h> +#endif + +#include <stdio.h> + +typedef unsigned char U_CHAR; + +/* This is used for communicating lists of keywords with cccp.c. */ +struct arglist { + struct arglist *next; + U_CHAR *name; + int length; + int argno; +}; + +/* Define a generic NULL if one hasn't already been defined. */ + +#ifndef NULL +#define NULL 0 +#endif + +#ifndef GENERIC_PTR +#if defined (USE_PROTOTYPES) ? USE_PROTOTYPES : defined (__STDC__) +#define GENERIC_PTR void * +#else +#define GENERIC_PTR char * +#endif +#endif + +/* Find the largest host integer type and set its size and type. */ + +#ifndef HOST_BITS_PER_WIDE_INT + +#if HOST_BITS_PER_LONG > HOST_BITS_PER_INT +#define HOST_BITS_PER_WIDE_INT HOST_BITS_PER_LONG +#define HOST_WIDE_INT long +#else +#define HOST_BITS_PER_WIDE_INT HOST_BITS_PER_INT +#define HOST_WIDE_INT int +#endif + +#endif + +#ifndef NULL_PTR +#define NULL_PTR ((GENERIC_PTR)0) +#endif + +int yylex (); +void yyerror (); +HOST_WIDE_INT expression_value; + +static jmp_buf parse_return_error; + +/* Nonzero means count most punctuation as part of a name. */ +static int keyword_parsing = 0; + +/* Nonzero means do not evaluate this expression. + This is a count, since unevaluated expressions can nest. */ +static int skip_evaluation; + +/* some external tables of character types */ +extern unsigned char is_idstart[], is_idchar[], is_hor_space[]; + +extern char *xmalloc (); + +/* Flag for -pedantic. */ +extern int pedantic; + +/* Flag for -traditional. */ +extern int traditional; + +#ifndef CHAR_TYPE_SIZE +#define CHAR_TYPE_SIZE BITS_PER_UNIT +#endif + +#ifndef INT_TYPE_SIZE +#define INT_TYPE_SIZE BITS_PER_WORD +#endif + +#ifndef LONG_TYPE_SIZE +#define LONG_TYPE_SIZE BITS_PER_WORD +#endif + +#ifndef WCHAR_TYPE_SIZE +#define WCHAR_TYPE_SIZE INT_TYPE_SIZE +#endif + +#ifndef MAX_CHAR_TYPE_SIZE +#define MAX_CHAR_TYPE_SIZE CHAR_TYPE_SIZE +#endif + +#ifndef MAX_INT_TYPE_SIZE +#define MAX_INT_TYPE_SIZE INT_TYPE_SIZE +#endif + +#ifndef MAX_LONG_TYPE_SIZE +#define MAX_LONG_TYPE_SIZE LONG_TYPE_SIZE +#endif + +#ifndef MAX_WCHAR_TYPE_SIZE +#define MAX_WCHAR_TYPE_SIZE WCHAR_TYPE_SIZE +#endif + +/* Yield nonzero if adding two numbers with A's and B's signs can yield a + number with SUM's sign, where A, B, and SUM are all C integers. */ +#define possible_sum_sign(a, b, sum) ((((a) ^ (b)) | ~ ((a) ^ (sum))) < 0) + +static void integer_overflow (); +static long left_shift (); +static long right_shift (); +%} + +%union { + struct constant {long value; int unsignedp;} integer; + struct name {U_CHAR *address; int length;} name; + struct arglist *keywords; +} + +%type <integer> exp exp1 start +%type <keywords> keywords +%token <integer> INT CHAR +%token <name> NAME +%token <integer> ERROR + +%right '?' ':' +%left ',' +%left OR +%left AND +%left '|' +%left '^' +%left '&' +%left EQUAL NOTEQUAL +%left '<' '>' LEQ GEQ +%left LSH RSH +%left '+' '-' +%left '*' '/' '%' +%right UNARY + +/* %expect 40 */ + +%% + +start : exp1 + { expression_value = $1.value; } + ; + +/* Expressions, including the comma operator. */ +exp1 : exp + | exp1 ',' exp + { if (pedantic) + pedwarn ("comma operator in operand of `#if'"); + $$ = $3; } + ; + +/* Expressions, not including the comma operator. */ +exp : '-' exp %prec UNARY + { $$.value = - $2.value; + if (($$.value & $2.value) < 0 && ! $2.unsignedp) + integer_overflow (); + $$.unsignedp = $2.unsignedp; } + | '!' exp %prec UNARY + { $$.value = ! $2.value; + $$.unsignedp = 0; } + | '+' exp %prec UNARY + { $$ = $2; } + | '~' exp %prec UNARY + { $$.value = ~ $2.value; + $$.unsignedp = $2.unsignedp; } + | '#' NAME + { $$.value = check_assertion ($2.address, $2.length, + 0, NULL_PTR); + $$.unsignedp = 0; } + | '#' NAME + { keyword_parsing = 1; } + '(' keywords ')' + { $$.value = check_assertion ($2.address, $2.length, + 1, $5); + keyword_parsing = 0; + $$.unsignedp = 0; } + | '(' exp1 ')' + { $$ = $2; } + ; + +/* Binary operators in order of decreasing precedence. */ +exp : exp '*' exp + { $$.unsignedp = $1.unsignedp || $3.unsignedp; + if ($$.unsignedp) + $$.value = (unsigned long) $1.value * $3.value; + else + { + $$.value = $1.value * $3.value; + if ($1.value + && ($$.value / $1.value != $3.value + || ($$.value & $1.value & $3.value) < 0)) + integer_overflow (); + } } + | exp '/' exp + { if ($3.value == 0) + { + if (!skip_evaluation) + error ("division by zero in #if"); + $3.value = 1; + } + $$.unsignedp = $1.unsignedp || $3.unsignedp; + if ($$.unsignedp) + $$.value = (unsigned long) $1.value / $3.value; + else + { + $$.value = $1.value / $3.value; + if (($$.value & $1.value & $3.value) < 0) + integer_overflow (); + } } + | exp '%' exp + { if ($3.value == 0) + { + if (!skip_evaluation) + error ("division by zero in #if"); + $3.value = 1; + } + $$.unsignedp = $1.unsignedp || $3.unsignedp; + if ($$.unsignedp) + $$.value = (unsigned long) $1.value % $3.value; + else + $$.value = $1.value % $3.value; } + | exp '+' exp + { $$.value = $1.value + $3.value; + $$.unsignedp = $1.unsignedp || $3.unsignedp; + if (! $$.unsignedp + && ! possible_sum_sign ($1.value, $3.value, + $$.value)) + integer_overflow (); } + | exp '-' exp + { $$.value = $1.value - $3.value; + $$.unsignedp = $1.unsignedp || $3.unsignedp; + if (! $$.unsignedp + && ! possible_sum_sign ($$.value, $3.value, + $1.value)) + integer_overflow (); } + | exp LSH exp + { $$.unsignedp = $1.unsignedp; + if ($3.value < 0 && ! $3.unsignedp) + $$.value = right_shift (&$1, -$3.value); + else + $$.value = left_shift (&$1, $3.value); } + | exp RSH exp + { $$.unsignedp = $1.unsignedp; + if ($3.value < 0 && ! $3.unsignedp) + $$.value = left_shift (&$1, -$3.value); + else + $$.value = right_shift (&$1, $3.value); } + | exp EQUAL exp + { $$.value = ($1.value == $3.value); + $$.unsignedp = 0; } + | exp NOTEQUAL exp + { $$.value = ($1.value != $3.value); + $$.unsignedp = 0; } + | exp LEQ exp + { $$.unsignedp = 0; + if ($1.unsignedp || $3.unsignedp) + $$.value = (unsigned long) $1.value <= $3.value; + else + $$.value = $1.value <= $3.value; } + | exp GEQ exp + { $$.unsignedp = 0; + if ($1.unsignedp || $3.unsignedp) + $$.value = (unsigned long) $1.value >= $3.value; + else + $$.value = $1.value >= $3.value; } + | exp '<' exp + { $$.unsignedp = 0; + if ($1.unsignedp || $3.unsignedp) + $$.value = (unsigned long) $1.value < $3.value; + else + $$.value = $1.value < $3.value; } + | exp '>' exp + { $$.unsignedp = 0; + if ($1.unsignedp || $3.unsignedp) + $$.value = (unsigned long) $1.value > $3.value; + else + $$.value = $1.value > $3.value; } + | exp '&' exp + { $$.value = $1.value & $3.value; + $$.unsignedp = $1.unsignedp || $3.unsignedp; } + | exp '^' exp + { $$.value = $1.value ^ $3.value; + $$.unsignedp = $1.unsignedp || $3.unsignedp; } + | exp '|' exp + { $$.value = $1.value | $3.value; + $$.unsignedp = $1.unsignedp || $3.unsignedp; } + | exp AND + { skip_evaluation += !$1.value; } + exp + { skip_evaluation -= !$1.value; + $$.value = ($1.value && $4.value); + $$.unsignedp = 0; } + | exp OR + { skip_evaluation += !!$1.value; } + exp + { skip_evaluation -= !!$1.value; + $$.value = ($1.value || $4.value); + $$.unsignedp = 0; } + | exp '?' + { skip_evaluation += !$1.value; } + exp ':' + { skip_evaluation += !!$1.value - !$1.value; } + exp + { skip_evaluation -= !!$1.value; + $$.value = $1.value ? $4.value : $7.value; + $$.unsignedp = $4.unsignedp || $7.unsignedp; } + | INT + { $$ = yylval.integer; } + | CHAR + { $$ = yylval.integer; } + | NAME + { $$.value = 0; + $$.unsignedp = 0; } + ; + +keywords : + { $$ = 0; } + | '(' keywords ')' keywords + { struct arglist *temp; + $$ = (struct arglist *) xmalloc (sizeof (struct arglist)); + $$->next = $2; + $$->name = (U_CHAR *) "("; + $$->length = 1; + temp = $$; + while (temp != 0 && temp->next != 0) + temp = temp->next; + temp->next = (struct arglist *) xmalloc (sizeof (struct arglist)); + temp->next->next = $4; + temp->next->name = (U_CHAR *) ")"; + temp->next->length = 1; } + | NAME keywords + { $$ = (struct arglist *) xmalloc (sizeof (struct arglist)); + $$->name = $1.address; + $$->length = $1.length; + $$->next = $2; } + ; +%% + +/* During parsing of a C expression, the pointer to the next character + is in this variable. */ + +static char *lexptr; + +/* Take care of parsing a number (anything that starts with a digit). + Set yylval and return the token type; update lexptr. + LEN is the number of characters in it. */ + +/* maybe needs to actually deal with floating point numbers */ + +int +parse_number (olen) + int olen; +{ + register char *p = lexptr; + register int c; + register unsigned long n = 0, nd, ULONG_MAX_over_base; + register int base = 10; + register int len = olen; + register int overflow = 0; + register int digit, largest_digit = 0; + int spec_long = 0; + + for (c = 0; c < len; c++) + if (p[c] == '.') { + /* It's a float since it contains a point. */ + yyerror ("floating point numbers not allowed in #if expressions"); + return ERROR; + } + + yylval.integer.unsignedp = 0; + + if (len >= 3 && (!strncmp (p, "0x", 2) || !strncmp (p, "0X", 2))) { + p += 2; + base = 16; + len -= 2; + } + else if (*p == '0') + base = 8; + + ULONG_MAX_over_base = (unsigned long) -1 / base; + + for (; len > 0; len--) { + c = *p++; + + if (c >= '0' && c <= '9') + digit = c - '0'; + else if (base == 16 && c >= 'a' && c <= 'f') + digit = c - 'a' + 10; + else if (base == 16 && c >= 'A' && c <= 'F') + digit = c - 'A' + 10; + else { + /* `l' means long, and `u' means unsigned. */ + while (1) { + if (c == 'l' || c == 'L') + { + if (spec_long) + yyerror ("two `l's in integer constant"); + spec_long = 1; + } + else if (c == 'u' || c == 'U') + { + if (yylval.integer.unsignedp) + yyerror ("two `u's in integer constant"); + yylval.integer.unsignedp = 1; + } + else + break; + + if (--len == 0) + break; + c = *p++; + } + /* Don't look for any more digits after the suffixes. */ + break; + } + if (largest_digit < digit) + largest_digit = digit; + nd = n * base + digit; + overflow |= ULONG_MAX_over_base < n | nd < n; + n = nd; + } + + if (len != 0) { + yyerror ("Invalid number in #if expression"); + return ERROR; + } + + if (base <= largest_digit) + warning ("integer constant contains digits beyond the radix"); + + if (overflow) + warning ("integer constant out of range"); + + /* If too big to be signed, consider it unsigned. */ + if ((long) n < 0 && ! yylval.integer.unsignedp) + { + if (base == 10) + warning ("integer constant is so large that it is unsigned"); + yylval.integer.unsignedp = 1; + } + + lexptr = p; + yylval.integer.value = n; + return INT; +} + +struct token { + char *operator; + int token; +}; + +static struct token tokentab2[] = { + {"&&", AND}, + {"||", OR}, + {"<<", LSH}, + {">>", RSH}, + {"==", EQUAL}, + {"!=", NOTEQUAL}, + {"<=", LEQ}, + {">=", GEQ}, + {"++", ERROR}, + {"--", ERROR}, + {NULL, ERROR} +}; + +/* Read one token, getting characters through lexptr. */ + +int +yylex () +{ + register int c; + register int namelen; + register unsigned char *tokstart; + register struct token *toktab; + int wide_flag; + + retry: + + tokstart = (unsigned char *) lexptr; + c = *tokstart; + /* See if it is a special token of length 2. */ + if (! keyword_parsing) + for (toktab = tokentab2; toktab->operator != NULL; toktab++) + if (c == *toktab->operator && tokstart[1] == toktab->operator[1]) { + lexptr += 2; + if (toktab->token == ERROR) + { + char *buf = (char *) alloca (40); + sprintf (buf, "`%s' not allowed in operand of `#if'", toktab->operator); + yyerror (buf); + } + return toktab->token; + } + + switch (c) { + case 0: + return 0; + + case ' ': + case '\t': + case '\r': + case '\n': + lexptr++; + goto retry; + + case 'L': + /* Capital L may start a wide-string or wide-character constant. */ + if (lexptr[1] == '\'') + { + lexptr++; + wide_flag = 1; + goto char_constant; + } + if (lexptr[1] == '"') + { + lexptr++; + wide_flag = 1; + goto string_constant; + } + break; + + case '\'': + wide_flag = 0; + char_constant: + lexptr++; + if (keyword_parsing) { + char *start_ptr = lexptr - 1; + while (1) { + c = *lexptr++; + if (c == '\\') + c = parse_escape (&lexptr); + else if (c == '\'') + break; + } + yylval.name.address = tokstart; + yylval.name.length = lexptr - start_ptr; + return NAME; + } + + /* This code for reading a character constant + handles multicharacter constants and wide characters. + It is mostly copied from c-lex.c. */ + { + register int result = 0; + register num_chars = 0; + unsigned width = MAX_CHAR_TYPE_SIZE; + int max_chars; + char *token_buffer; + + if (wide_flag) + { + width = MAX_WCHAR_TYPE_SIZE; +#ifdef MULTIBYTE_CHARS + max_chars = MB_CUR_MAX; +#else + max_chars = 1; +#endif + } + else + max_chars = MAX_LONG_TYPE_SIZE / width; + + token_buffer = (char *) alloca (max_chars + 1); + + while (1) + { + c = *lexptr++; + + if (c == '\'' || c == EOF) + break; + + if (c == '\\') + { + c = parse_escape (&lexptr); + if (width < HOST_BITS_PER_INT + && (unsigned) c >= (1 << width)) + pedwarn ("escape sequence out of range for character"); + } + + num_chars++; + + /* Merge character into result; ignore excess chars. */ + if (num_chars < max_chars + 1) + { + if (width < HOST_BITS_PER_INT) + result = (result << width) | (c & ((1 << width) - 1)); + else + result = c; + token_buffer[num_chars - 1] = c; + } + } + + token_buffer[num_chars] = 0; + + if (c != '\'') + error ("malformatted character constant"); + else if (num_chars == 0) + error ("empty character constant"); + else if (num_chars > max_chars) + { + num_chars = max_chars; + error ("character constant too long"); + } + else if (num_chars != 1 && ! traditional) + warning ("multi-character character constant"); + + /* If char type is signed, sign-extend the constant. */ + if (! wide_flag) + { + int num_bits = num_chars * width; + + if (lookup ("__CHAR_UNSIGNED__", sizeof ("__CHAR_UNSIGNED__")-1, -1) + || ((result >> (num_bits - 1)) & 1) == 0) + yylval.integer.value + = result & ((unsigned long) ~0 >> (HOST_BITS_PER_LONG - num_bits)); + else + yylval.integer.value + = result | ~((unsigned long) ~0 >> (HOST_BITS_PER_LONG - num_bits)); + } + else + { +#ifdef MULTIBYTE_CHARS + /* Set the initial shift state and convert the next sequence. */ + result = 0; + /* In all locales L'\0' is zero and mbtowc will return zero, + so don't use it. */ + if (num_chars > 1 + || (num_chars == 1 && token_buffer[0] != '\0')) + { + wchar_t wc; + (void) mbtowc (NULL_PTR, NULL_PTR, 0); + if (mbtowc (& wc, token_buffer, num_chars) == num_chars) + result = wc; + else + warning ("Ignoring invalid multibyte character"); + } +#endif + yylval.integer.value = result; + } + } + + /* This is always a signed type. */ + yylval.integer.unsignedp = 0; + + return CHAR; + + /* some of these chars are invalid in constant expressions; + maybe do something about them later */ + case '/': + case '+': + case '-': + case '*': + case '%': + case '|': + case '&': + case '^': + case '~': + case '!': + case '@': + case '<': + case '>': + case '[': + case ']': + case '.': + case '?': + case ':': + case '=': + case '{': + case '}': + case ',': + case '#': + if (keyword_parsing) + break; + case '(': + case ')': + lexptr++; + return c; + + case '"': + string_constant: + if (keyword_parsing) { + char *start_ptr = lexptr; + lexptr++; + while (1) { + c = *lexptr++; + if (c == '\\') + c = parse_escape (&lexptr); + else if (c == '"') + break; + } + yylval.name.address = tokstart; + yylval.name.length = lexptr - start_ptr; + return NAME; + } + yyerror ("string constants not allowed in #if expressions"); + return ERROR; + } + + if (c >= '0' && c <= '9' && !keyword_parsing) { + /* It's a number */ + for (namelen = 0; + c = tokstart[namelen], is_idchar[c] || c == '.'; + namelen++) + ; + return parse_number (namelen); + } + + /* It is a name. See how long it is. */ + + if (keyword_parsing) { + for (namelen = 0;; namelen++) { + if (is_hor_space[tokstart[namelen]]) + break; + if (tokstart[namelen] == '(' || tokstart[namelen] == ')') + break; + if (tokstart[namelen] == '"' || tokstart[namelen] == '\'') + break; + } + } else { + if (!is_idstart[c]) { + yyerror ("Invalid token in expression"); + return ERROR; + } + + for (namelen = 0; is_idchar[tokstart[namelen]]; namelen++) + ; + } + + lexptr += namelen; + yylval.name.address = tokstart; + yylval.name.length = namelen; + return NAME; +} + + +/* 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)++; + switch (c) + { + case 'a': + return TARGET_BELL; + case 'b': + return TARGET_BS; + case 'e': + case 'E': + if (pedantic) + pedwarn ("non-ANSI-standard escape sequence, `\\%c'", c); + return 033; + case 'f': + return TARGET_FF; + case 'n': + return TARGET_NEWLINE; + case 'r': + return TARGET_CR; + case 't': + return TARGET_TAB; + case 'v': + return TARGET_VT; + case '\n': + return -2; + case 0: + (*string_ptr)--; + return 0; + + case '0': + case '1': + case '2': + case '3': + case '4': + case '5': + case '6': + case '7': + { + register int i = c - '0'; + register int count = 0; + while (++count < 3) + { + c = *(*string_ptr)++; + if (c >= '0' && c <= '7') + i = (i << 3) + c - '0'; + else + { + (*string_ptr)--; + break; + } + } + if ((i & ~((1 << MAX_CHAR_TYPE_SIZE) - 1)) != 0) + { + i &= (1 << MAX_CHAR_TYPE_SIZE) - 1; + warning ("octal character constant does not fit in a byte"); + } + return i; + } + case 'x': + { + register unsigned i = 0, overflow = 0, digits_found = 0, digit; + for (;;) + { + c = *(*string_ptr)++; + if (c >= '0' && c <= '9') + digit = c - '0'; + else if (c >= 'a' && c <= 'f') + digit = c - 'a' + 10; + else if (c >= 'A' && c <= 'F') + digit = c - 'A' + 10; + else + { + (*string_ptr)--; + break; + } + overflow |= i ^ (i << 4 >> 4); + i = (i << 4) + digit; + digits_found = 1; + } + if (!digits_found) + yyerror ("\\x used with no following hex digits"); + if (overflow | (i & ~((1 << BITS_PER_UNIT) - 1))) + { + i &= (1 << BITS_PER_UNIT) - 1; + warning ("hex character constant does not fit in a byte"); + } + return i; + } + default: + return c; + } +} + +void +yyerror (s) + char *s; +{ + error (s); + skip_evaluation = 0; + longjmp (parse_return_error, 1); +} + +static void +integer_overflow () +{ + if (!skip_evaluation && pedantic) + pedwarn ("integer overflow in preprocessor expression"); +} + +static long +left_shift (a, b) + struct constant *a; + unsigned long b; +{ + /* It's unclear from the C standard whether shifts can overflow. + The following code ignores overflow; perhaps a C standard + interpretation ruling is needed. */ + if (b >= HOST_BITS_PER_LONG) + return 0; + else if (a->unsignedp) + return (unsigned long) a->value << b; + else + return a->value << b; +} + +static long +right_shift (a, b) + struct constant *a; + unsigned long b; +{ + if (b >= HOST_BITS_PER_LONG) + return a->unsignedp ? 0 : a->value >> (HOST_BITS_PER_LONG - 1); + else if (a->unsignedp) + return (unsigned long) a->value >> b; + else + return a->value >> b; +} + +/* This page contains the entry point to this file. */ + +/* Parse STRING as an expression, and complain if this fails + to use up all of the contents of STRING. */ +/* We do not support C comments. They should be removed before + this function is called. */ + +HOST_WIDE_INT +parse_c_expression (string) + char *string; +{ + lexptr = string; + + if (lexptr == 0 || *lexptr == 0) { + error ("empty #if expression"); + return 0; /* don't include the #if group */ + } + + /* if there is some sort of scanning error, just return 0 and assume + the parsing routine has printed an error message somewhere. + there is surely a better thing to do than this. */ + if (setjmp (parse_return_error)) + return 0; + + if (yyparse ()) + return 0; /* actually this is never reached + the way things stand. */ + if (*lexptr) + error ("Junk after end of expression."); + + return expression_value; /* set by yyparse () */ +} + +#ifdef TEST_EXP_READER +extern int yydebug; + +/* Main program for testing purposes. */ +int +main () +{ + int n, c; + char buf[1024]; + +/* + yydebug = 1; +*/ + initialize_random_junk (); + + for (;;) { + printf ("enter expression: "); + n = 0; + while ((buf[n] = getchar ()) != '\n' && buf[n] != EOF) + n++; + if (buf[n] == EOF) + break; + buf[n] = '\0'; + printf ("parser returned %ld\n", parse_c_expression (buf)); + } + + return 0; +} + +/* table to tell if char can be part of a C identifier. */ +unsigned char is_idchar[256]; +/* table to tell if char can be first char of a c identifier. */ +unsigned char is_idstart[256]; +/* table to tell if c is horizontal space. isspace () thinks that + newline is space; this is not a good idea for this program. */ +char is_hor_space[256]; + +/* + * initialize random junk in the hash table and maybe other places + */ +initialize_random_junk () +{ + register int i; + + /* + * Set up is_idchar and is_idstart tables. These should be + * faster than saying (is_alpha (c) || c == '_'), etc. + * Must do set up these things before calling any routines tthat + * refer to them. + */ + for (i = 'a'; i <= 'z'; i++) { + ++is_idchar[i - 'a' + 'A']; + ++is_idchar[i]; + ++is_idstart[i - 'a' + 'A']; + ++is_idstart[i]; + } + for (i = '0'; i <= '9'; i++) + ++is_idchar[i]; + ++is_idchar['_']; + ++is_idstart['_']; +#if DOLLARS_IN_IDENTIFIERS + ++is_idchar['$']; + ++is_idstart['$']; +#endif + + /* horizontal space table */ + ++is_hor_space[' ']; + ++is_hor_space['\t']; +} + +error (msg) +{ + printf ("error: %s\n", msg); +} + +warning (msg) +{ + printf ("warning: %s\n", msg); +} + +struct hashnode * +lookup (name, len, hash) + char *name; + int len; + int hash; +{ + return (DEFAULT_SIGNED_CHAR) ? 0 : ((struct hashnode *) -1); +} +#endif |
