82 lines
2.0 KiB
C
82 lines
2.0 KiB
C
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// Copyright (c) 1993-1999 Microsoft Corporation
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#include "y2.h"
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int
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defin( int t, register char *s )
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{
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/* define s to be a terminal if t=0
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or a nonterminal if t=1 */
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register val;
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if (t)
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{
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if( ++nnonter >= NNONTERM ) error("too many nonterminals, limit %d",NNONTERM);
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nontrst[nnonter].name = cstash(s);
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return( NTBASE + nnonter );
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}
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/* must be a token */
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if( ++ntokens >= NTERMS ) error("too many terminals, limit %d",NTERMS );
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tokset[ntokens].name = cstash(s);
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/* establish value for token */
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if( s[0]==' ' && s[2]=='\0' ) /* single character literal */
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val = s[1];
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else if ( s[0]==' ' && s[1]=='\\' )
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{
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/* escape sequence */
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if( s[3] == '\0' )
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{
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/* single character escape sequence */
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switch ( s[2] )
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{
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/* character which is escaped */
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case 'n':
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val = '\n';
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break;
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case 'r':
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val = '\r';
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break;
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case 'b':
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val = '\b';
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break;
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case 't':
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val = '\t';
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break;
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case 'f':
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val = '\f';
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break;
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case '\'':
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val = '\'';
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break;
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case '"':
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val = '"';
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break;
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case '\\':
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val = '\\';
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break;
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default:
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error( "invalid escape" );
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}
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}
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else if( s[2] <= '7' && s[2]>='0' )
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{
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/* \nnn sequence */
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if( s[3]<'0' || s[3] > '7' || s[4]<'0' ||
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s[4]>'7' || s[5] != '\0' ) error("illegal \\nnn construction" );
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val = 64*s[2] + 8*s[3] + s[4] - 73*'0';
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if( val == 0 ) error( "'\\000' is illegal" );
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}
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}
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else
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{
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val = extval++;
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}
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tokset[ntokens].value = val;
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toklev[ntokens] = 0;
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return( ntokens );
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}
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