[BACK]Return to awkgram.y CVS log [TXT][DIR] Up to [local] / src / usr.bin / awk

Annotation of src/usr.bin/awk/awkgram.y, Revision 1.4

1.4     ! kstailey    1: /*     $OpenBSD$       */
1.1       tholo       2: /****************************************************************
1.4     ! kstailey    3: Copyright (C) Lucent Technologies 1997
1.1       tholo       4: All Rights Reserved
                      5:
                      6: Permission to use, copy, modify, and distribute this software and
                      7: its documentation for any purpose and without fee is hereby
                      8: granted, provided that the above copyright notice appear in all
                      9: copies and that both that the copyright notice and this
                     10: permission notice and warranty disclaimer appear in supporting
1.4     ! kstailey   11: documentation, and that the name Lucent Technologies or any of
        !            12: its entities not be used in advertising or publicity pertaining
        !            13: to distribution of the software without specific, written prior
        !            14: permission.
        !            15:
        !            16: LUCENT DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
        !            17: INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS.
        !            18: IN NO EVENT SHALL LUCENT OR ANY OF ITS ENTITIES BE LIABLE FOR ANY
        !            19: SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
        !            20: WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER
        !            21: IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
        !            22: ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF
        !            23: THIS SOFTWARE.
1.1       tholo      24: ****************************************************************/
                     25:
                     26: %{
                     27: #include <stdio.h>
                     28: #include <string.h>
                     29: #include "awk.h"
                     30:
                     31: void checkdup(Node *list, Cell *item);
                     32: int yywrap(void) { return(1); }
                     33:
                     34: Node   *beginloc = 0;
                     35: Node   *endloc = 0;
                     36: int    infunc  = 0;    /* = 1 if in arglist or body of func */
                     37: int    inloop  = 0;    /* = 1 if in while, for, do */
                     38: char   *curfname = 0;  /* current function name */
                     39: Node   *arglist = 0;   /* list of args for current function */
                     40: %}
                     41:
                     42: %union {
                     43:        Node    *p;
                     44:        Cell    *cp;
1.3       millert    45:        int     i;
1.1       tholo      46:        char    *s;
                     47: }
                     48:
                     49: %token <i>     FIRSTTOKEN      /* must be first */
                     50: %token <p>     PROGRAM PASTAT PASTAT2 XBEGIN XEND
                     51: %token <i>     NL ',' '{' '(' '|' ';' '/' ')' '}' '[' ']'
                     52: %token <i>     ARRAY
                     53: %token <i>     MATCH NOTMATCH MATCHOP
                     54: %token <i>     FINAL DOT ALL CCL NCCL CHAR OR STAR QUEST PLUS
                     55: %token <i>     AND BOR APPEND EQ GE GT LE LT NE IN
                     56: %token <i>     ARG BLTIN BREAK CLOSE CONTINUE DELETE DO EXIT FOR FUNC
                     57: %token <i>     SUB GSUB IF INDEX LSUBSTR MATCHFCN NEXT NEXTFILE
                     58: %token <i>     ADD MINUS MULT DIVIDE MOD
                     59: %token <i>     ASSIGN ASGNOP ADDEQ SUBEQ MULTEQ DIVEQ MODEQ POWEQ
                     60: %token <i>     PRINT PRINTF SPRINTF
                     61: %token <p>     ELSE INTEST CONDEXPR
                     62: %token <i>     POSTINCR PREINCR POSTDECR PREDECR
1.4     ! kstailey   63: %token <cp>    VAR IVAR VARNF CALL NUMBER STRING
1.1       tholo      64: %token <s>     REGEXPR
                     65:
                     66: %type  <p>     pas pattern ppattern plist pplist patlist prarg term re
                     67: %type  <p>     pa_pat pa_stat pa_stats
                     68: %type  <s>     reg_expr
                     69: %type  <p>     simple_stmt opt_simple_stmt stmt stmtlist
                     70: %type  <p>     var varname funcname varlist
                     71: %type  <p>     for if else while
                     72: %type  <i>     do st
                     73: %type  <i>     pst opt_pst lbrace rbrace rparen comma nl opt_nl and bor
                     74: %type  <i>     subop print
                     75:
                     76: %right ASGNOP
                     77: %right '?'
                     78: %right ':'
                     79: %left  BOR
                     80: %left  AND
                     81: %left  GETLINE
                     82: %nonassoc APPEND EQ GE GT LE LT NE MATCHOP IN '|'
1.4     ! kstailey   83: %left  ARG BLTIN BREAK CALL CLOSE CONTINUE DELETE DO EXIT FOR FUNC
1.1       tholo      84: %left  GSUB IF INDEX LSUBSTR MATCHFCN NEXT NUMBER
                     85: %left  PRINT PRINTF RETURN SPLIT SPRINTF STRING SUB SUBSTR
                     86: %left  REGEXPR VAR VARNF IVAR WHILE '('
                     87: %left  CAT
                     88: %left  '+' '-'
                     89: %left  '*' '/' '%'
                     90: %left  NOT UMINUS
                     91: %right POWER
                     92: %right DECR INCR
                     93: %left  INDIRECT
                     94: %token LASTTOKEN       /* must be last */
                     95:
                     96: %%
                     97:
                     98: program:
                     99:          pas   { if (errorflag==0)
                    100:                        winner = (Node *)stat3(PROGRAM, beginloc, $1, endloc); }
                    101:        | error { yyclearin; bracecheck(); ERROR "bailing out" SYNTAX; }
                    102:        ;
                    103:
                    104: and:
                    105:          AND | and NL
                    106:        ;
                    107:
                    108: bor:
                    109:          BOR | bor NL
                    110:        ;
                    111:
                    112: comma:
                    113:          ',' | comma NL
                    114:        ;
                    115:
                    116: do:
                    117:          DO | do NL
                    118:        ;
                    119:
                    120: else:
                    121:          ELSE | else NL
                    122:        ;
                    123:
                    124: for:
                    125:          FOR '(' opt_simple_stmt ';' opt_nl pattern ';' opt_nl opt_simple_stmt rparen {inloop++;} stmt
                    126:                { --inloop; $$ = stat4(FOR, $3, notnull($6), $9, $12); }
                    127:        | FOR '(' opt_simple_stmt ';'  ';' opt_nl opt_simple_stmt rparen {inloop++;} stmt
                    128:                { --inloop; $$ = stat4(FOR, $3, NIL, $7, $10); }
                    129:        | FOR '(' varname IN varname rparen {inloop++;} stmt
                    130:                { --inloop; $$ = stat3(IN, $3, makearr($5), $8); }
                    131:        ;
                    132:
                    133: funcname:
                    134:          VAR   { setfname($1); }
                    135:        | CALL  { setfname($1); }
                    136:        ;
                    137:
                    138: if:
                    139:          IF '(' pattern rparen         { $$ = notnull($3); }
                    140:        ;
                    141:
                    142: lbrace:
                    143:          '{' | lbrace NL
                    144:        ;
                    145:
                    146: nl:
                    147:          NL | nl NL
                    148:        ;
                    149:
                    150: opt_nl:
                    151:          /* empty */   { $$ = 0; }
                    152:        | nl
                    153:        ;
                    154:
                    155: opt_pst:
                    156:          /* empty */   { $$ = 0; }
                    157:        | pst
                    158:        ;
                    159:
                    160:
                    161: opt_simple_stmt:
                    162:          /* empty */                   { $$ = 0; }
                    163:        | simple_stmt
                    164:        ;
                    165:
                    166: pas:
                    167:          opt_pst                       { $$ = 0; }
                    168:        | opt_pst pa_stats opt_pst      { $$ = $2; }
                    169:        ;
                    170:
                    171: pa_pat:
                    172:          pattern       { $$ = notnull($1); }
                    173:        ;
                    174:
                    175: pa_stat:
                    176:          pa_pat                        { $$ = stat2(PASTAT, $1, stat2(PRINT, rectonode(), NIL)); }
                    177:        | pa_pat lbrace stmtlist '}'    { $$ = stat2(PASTAT, $1, $3); }
                    178:        | pa_pat ',' pa_pat             { $$ = pa2stat($1, $3, stat2(PRINT, rectonode(), NIL)); }
                    179:        | pa_pat ',' pa_pat lbrace stmtlist '}' { $$ = pa2stat($1, $3, $5); }
                    180:        | lbrace stmtlist '}'           { $$ = stat2(PASTAT, NIL, $2); }
                    181:        | XBEGIN lbrace stmtlist '}'
                    182:                { beginloc = linkum(beginloc, $3); $$ = 0; }
                    183:        | XEND lbrace stmtlist '}'
                    184:                { endloc = linkum(endloc, $3); $$ = 0; }
                    185:        | FUNC funcname '(' varlist rparen {infunc++;} lbrace stmtlist '}'
                    186:                { infunc--; curfname=0; defn((Cell *)$2, $4, $8); $$ = 0; }
                    187:        ;
                    188:
                    189: pa_stats:
                    190:          pa_stat
                    191:        | pa_stats opt_pst pa_stat      { $$ = linkum($1, $3); }
                    192:        ;
                    193:
                    194: patlist:
                    195:          pattern
                    196:        | patlist comma pattern         { $$ = linkum($1, $3); }
                    197:        ;
                    198:
                    199: ppattern:
                    200:          var ASGNOP ppattern           { $$ = op2($2, $1, $3); }
                    201:        | ppattern '?' ppattern ':' ppattern %prec '?'
                    202:                { $$ = op3(CONDEXPR, notnull($1), $3, $5); }
                    203:        | ppattern bor ppattern %prec BOR
                    204:                { $$ = op2(BOR, notnull($1), notnull($3)); }
                    205:        | ppattern and ppattern %prec AND
                    206:                { $$ = op2(AND, notnull($1), notnull($3)); }
                    207:        | ppattern MATCHOP reg_expr     { $$ = op3($2, NIL, $1, (Node*)makedfa($3, 0)); }
                    208:        | ppattern MATCHOP ppattern
                    209:                { if (constnode($3))
                    210:                        $$ = op3($2, NIL, $1, (Node*)makedfa(strnode($3), 0));
                    211:                  else
                    212:                        $$ = op3($2, (Node *)1, $1, $3); }
                    213:        | ppattern IN varname           { $$ = op2(INTEST, $1, makearr($3)); }
                    214:        | '(' plist ')' IN varname      { $$ = op2(INTEST, $2, makearr($5)); }
                    215:        | ppattern term %prec CAT       { $$ = op2(CAT, $1, $2); }
                    216:        | re
                    217:        | term
                    218:        ;
                    219:
                    220: pattern:
                    221:          var ASGNOP pattern            { $$ = op2($2, $1, $3); }
                    222:        | pattern '?' pattern ':' pattern %prec '?'
                    223:                { $$ = op3(CONDEXPR, notnull($1), $3, $5); }
                    224:        | pattern bor pattern %prec BOR
                    225:                { $$ = op2(BOR, notnull($1), notnull($3)); }
                    226:        | pattern and pattern %prec AND
                    227:                { $$ = op2(AND, notnull($1), notnull($3)); }
                    228:        | pattern EQ pattern            { $$ = op2($2, $1, $3); }
                    229:        | pattern GE pattern            { $$ = op2($2, $1, $3); }
                    230:        | pattern GT pattern            { $$ = op2($2, $1, $3); }
                    231:        | pattern LE pattern            { $$ = op2($2, $1, $3); }
                    232:        | pattern LT pattern            { $$ = op2($2, $1, $3); }
                    233:        | pattern NE pattern            { $$ = op2($2, $1, $3); }
                    234:        | pattern MATCHOP reg_expr      { $$ = op3($2, NIL, $1, (Node*)makedfa($3, 0)); }
                    235:        | pattern MATCHOP pattern
                    236:                { if (constnode($3))
                    237:                        $$ = op3($2, NIL, $1, (Node*)makedfa(strnode($3), 0));
                    238:                  else
                    239:                        $$ = op3($2, (Node *)1, $1, $3); }
                    240:        | pattern IN varname            { $$ = op2(INTEST, $1, makearr($3)); }
                    241:        | '(' plist ')' IN varname      { $$ = op2(INTEST, $2, makearr($5)); }
1.4     ! kstailey  242:        | pattern '|' GETLINE var       {
        !           243:                        if (safe) ERROR "cmd | getline is unsafe" SYNTAX;
        !           244:                        else $$ = op3(GETLINE, $4, (Node*)$2, $1); }
        !           245:        | pattern '|' GETLINE           {
        !           246:                        if (safe) ERROR "cmd | getline is unsafe" SYNTAX;
        !           247:                        else $$ = op3(GETLINE, (Node*)0, (Node*)$2, $1); }
1.1       tholo     248:        | pattern term %prec CAT        { $$ = op2(CAT, $1, $2); }
                    249:        | re
                    250:        | term
                    251:        ;
                    252:
                    253: plist:
                    254:          pattern comma pattern         { $$ = linkum($1, $3); }
                    255:        | plist comma pattern           { $$ = linkum($1, $3); }
                    256:        ;
                    257:
                    258: pplist:
                    259:          ppattern
                    260:        | pplist comma ppattern         { $$ = linkum($1, $3); }
                    261:        ;
                    262:
                    263: prarg:
                    264:          /* empty */                   { $$ = rectonode(); }
                    265:        | pplist
                    266:        | '(' plist ')'                 { $$ = $2; }
                    267:        ;
                    268:
                    269: print:
                    270:          PRINT | PRINTF
                    271:        ;
                    272:
                    273: pst:
                    274:          NL | ';' | pst NL | pst ';'
                    275:        ;
                    276:
                    277: rbrace:
                    278:          '}' | rbrace NL
                    279:        ;
                    280:
                    281: re:
                    282:           reg_expr
                    283:                { $$ = op3(MATCH, NIL, rectonode(), (Node*)makedfa($1, 0)); }
                    284:        | NOT re        { $$ = op1(NOT, notnull($2)); }
                    285:        ;
                    286:
                    287: reg_expr:
                    288:          '/' {startreg();} REGEXPR '/'         { $$ = $3; }
                    289:        ;
                    290:
                    291: rparen:
                    292:          ')' | rparen NL
                    293:        ;
                    294:
                    295: simple_stmt:
1.4     ! kstailey  296:          print prarg '|' term          {
        !           297:                        if (safe) ERROR "print | is unsafe" SYNTAX;
        !           298:                        else $$ = stat3($1, $2, (Node *) $3, $4); }
        !           299:        | print prarg APPEND term       {
        !           300:                        if (safe) ERROR "print >> is unsafe" SYNTAX;
        !           301:                        else $$ = stat3($1, $2, (Node *) $3, $4); }
        !           302:        | print prarg GT term           {
        !           303:                        if (safe) ERROR "print > is unsafe" SYNTAX;
        !           304:                        else $$ = stat3($1, $2, (Node *) $3, $4); }
1.1       tholo     305:        | print prarg                   { $$ = stat3($1, $2, NIL, NIL); }
                    306:        | DELETE varname '[' patlist ']' { $$ = stat2(DELETE, makearr($2), $4); }
                    307:        | DELETE varname                 { $$ = stat2(DELETE, makearr($2), 0); }
                    308:        | pattern                       { $$ = exptostat($1); }
                    309:        | error                         { yyclearin; ERROR "illegal statement" SYNTAX; }
                    310:        ;
                    311:
                    312: st:
                    313:          nl
                    314:        | ';' opt_nl
                    315:        ;
                    316:
                    317: stmt:
                    318:          BREAK st              { if (!inloop) ERROR "break illegal outside of loops" SYNTAX;
                    319:                                  $$ = stat1(BREAK, NIL); }
                    320:        | CLOSE pattern st      { $$ = stat1(CLOSE, $2); }
                    321:        | CONTINUE st           {  if (!inloop) ERROR "continue illegal outside of loops" SYNTAX;
                    322:                                  $$ = stat1(CONTINUE, NIL); }
                    323:        | do {inloop++;} stmt {--inloop;} WHILE '(' pattern ')' st
                    324:                { $$ = stat2(DO, $3, notnull($7)); }
                    325:        | EXIT pattern st       { $$ = stat1(EXIT, $2); }
                    326:        | EXIT st               { $$ = stat1(EXIT, NIL); }
                    327:        | for
                    328:        | if stmt else stmt     { $$ = stat3(IF, $1, $2, $4); }
                    329:        | if stmt               { $$ = stat3(IF, $1, $2, NIL); }
                    330:        | lbrace stmtlist rbrace { $$ = $2; }
                    331:        | NEXT st       { if (infunc)
                    332:                                ERROR "next is illegal inside a function" SYNTAX;
                    333:                          $$ = stat1(NEXT, NIL); }
                    334:        | NEXTFILE st   { if (infunc)
                    335:                                ERROR "nextfile is illegal inside a function" SYNTAX;
                    336:                          $$ = stat1(NEXTFILE, NIL); }
                    337:        | RETURN pattern st     { $$ = stat1(RETURN, $2); }
                    338:        | RETURN st             { $$ = stat1(RETURN, NIL); }
                    339:        | simple_stmt st
                    340:        | while {inloop++;} stmt        { --inloop; $$ = stat2(WHILE, $1, $3); }
                    341:        | ';' opt_nl            { $$ = 0; }
                    342:        ;
                    343:
                    344: stmtlist:
                    345:          stmt
                    346:        | stmtlist stmt         { $$ = linkum($1, $2); }
                    347:        ;
                    348:
                    349: subop:
                    350:          SUB | GSUB
                    351:        ;
                    352:
                    353: term:
                    354:          term '+' term                 { $$ = op2(ADD, $1, $3); }
                    355:        | term '-' term                 { $$ = op2(MINUS, $1, $3); }
                    356:        | term '*' term                 { $$ = op2(MULT, $1, $3); }
                    357:        | term '/' term                 { $$ = op2(DIVIDE, $1, $3); }
                    358:        | term '%' term                 { $$ = op2(MOD, $1, $3); }
                    359:        | term POWER term               { $$ = op2(POWER, $1, $3); }
                    360:        | '-' term %prec UMINUS         { $$ = op1(UMINUS, $2); }
                    361:        | '+' term %prec UMINUS         { $$ = $2; }
                    362:        | NOT term %prec UMINUS         { $$ = op1(NOT, notnull($2)); }
                    363:        | BLTIN '(' ')'                 { $$ = op2(BLTIN, (Node *) $1, rectonode()); }
                    364:        | BLTIN '(' patlist ')'         { $$ = op2(BLTIN, (Node *) $1, $3); }
                    365:        | BLTIN                         { $$ = op2(BLTIN, (Node *) $1, rectonode()); }
1.4     ! kstailey  366:        | CALL '(' ')'                  { $$ = op2(CALL, celltonode($1,CVAR), NIL); }
        !           367:        | CALL '(' patlist ')'          { $$ = op2(CALL, celltonode($1,CVAR), $3); }
1.1       tholo     368:        | DECR var                      { $$ = op1(PREDECR, $2); }
                    369:        | INCR var                      { $$ = op1(PREINCR, $2); }
                    370:        | var DECR                      { $$ = op1(POSTDECR, $1); }
                    371:        | var INCR                      { $$ = op1(POSTINCR, $1); }
                    372:        | GETLINE var LT term           { $$ = op3(GETLINE, $2, (Node *)$3, $4); }
                    373:        | GETLINE LT term               { $$ = op3(GETLINE, NIL, (Node *)$2, $3); }
                    374:        | GETLINE var                   { $$ = op3(GETLINE, $2, NIL, NIL); }
                    375:        | GETLINE                       { $$ = op3(GETLINE, NIL, NIL, NIL); }
                    376:        | INDEX '(' pattern comma pattern ')'
                    377:                { $$ = op2(INDEX, $3, $5); }
                    378:        | INDEX '(' pattern comma reg_expr ')'
                    379:                { ERROR "index() doesn't permit regular expressions" SYNTAX;
                    380:                  $$ = op2(INDEX, $3, (Node*)$5); }
                    381:        | '(' pattern ')'               { $$ = $2; }
                    382:        | MATCHFCN '(' pattern comma reg_expr ')'
                    383:                { $$ = op3(MATCHFCN, NIL, $3, (Node*)makedfa($5, 1)); }
                    384:        | MATCHFCN '(' pattern comma pattern ')'
                    385:                { if (constnode($5))
                    386:                        $$ = op3(MATCHFCN, NIL, $3, (Node*)makedfa(strnode($5), 1));
                    387:                  else
                    388:                        $$ = op3(MATCHFCN, (Node *)1, $3, $5); }
1.4     ! kstailey  389:        | NUMBER                        { $$ = celltonode($1, CCON); }
1.1       tholo     390:        | SPLIT '(' pattern comma varname comma pattern ')'     /* string */
                    391:                { $$ = op4(SPLIT, $3, makearr($5), $7, (Node*)STRING); }
                    392:        | SPLIT '(' pattern comma varname comma reg_expr ')'    /* const /regexp/ */
                    393:                { $$ = op4(SPLIT, $3, makearr($5), (Node*)makedfa($7, 1), (Node *)REGEXPR); }
                    394:        | SPLIT '(' pattern comma varname ')'
                    395:                { $$ = op4(SPLIT, $3, makearr($5), NIL, (Node*)STRING); }  /* default */
                    396:        | SPRINTF '(' patlist ')'       { $$ = op1($1, $3); }
1.4     ! kstailey  397:        | STRING                        { $$ = celltonode($1, CCON); }
1.1       tholo     398:        | subop '(' reg_expr comma pattern ')'
                    399:                { $$ = op4($1, NIL, (Node*)makedfa($3, 1), $5, rectonode()); }
                    400:        | subop '(' pattern comma pattern ')'
                    401:                { if (constnode($3))
                    402:                        $$ = op4($1, NIL, (Node*)makedfa(strnode($3), 1), $5, rectonode());
                    403:                  else
                    404:                        $$ = op4($1, (Node *)1, $3, $5, rectonode()); }
                    405:        | subop '(' reg_expr comma pattern comma var ')'
                    406:                { $$ = op4($1, NIL, (Node*)makedfa($3, 1), $5, $7); }
                    407:        | subop '(' pattern comma pattern comma var ')'
                    408:                { if (constnode($3))
                    409:                        $$ = op4($1, NIL, (Node*)makedfa(strnode($3), 1), $5, $7);
                    410:                  else
                    411:                        $$ = op4($1, (Node *)1, $3, $5, $7); }
                    412:        | SUBSTR '(' pattern comma pattern comma pattern ')'
                    413:                { $$ = op3(SUBSTR, $3, $5, $7); }
                    414:        | SUBSTR '(' pattern comma pattern ')'
                    415:                { $$ = op3(SUBSTR, $3, $5, NIL); }
                    416:        | var
                    417:        ;
                    418:
                    419: var:
                    420:          varname
                    421:        | varname '[' patlist ']'       { $$ = op2(ARRAY, makearr($1), $3); }
1.4     ! kstailey  422:        | IVAR                          { $$ = op1(INDIRECT, celltonode($1, CVAR)); }
1.1       tholo     423:        | INDIRECT term                 { $$ = op1(INDIRECT, $2); }
                    424:        ;
                    425:
                    426: varlist:
                    427:          /* nothing */         { arglist = $$ = 0; }
1.4     ! kstailey  428:        | VAR                   { arglist = $$ = celltonode($1,CVAR); }
1.1       tholo     429:        | varlist comma VAR     {
                    430:                        checkdup($1, $3);
1.4     ! kstailey  431:                        arglist = $$ = linkum($1,celltonode($3,CVAR)); }
1.1       tholo     432:        ;
                    433:
                    434: varname:
1.4     ! kstailey  435:          VAR                   { $$ = celltonode($1, CVAR); }
1.1       tholo     436:        | ARG                   { $$ = op1(ARG, (Node *) $1); }
                    437:        | VARNF                 { $$ = op1(VARNF, (Node *) $1); }
                    438:        ;
                    439:
                    440:
                    441: while:
                    442:          WHILE '(' pattern rparen      { $$ = notnull($3); }
                    443:        ;
                    444:
                    445: %%
                    446:
                    447: void setfname(Cell *p)
                    448: {
                    449:        if (isarr(p))
                    450:                ERROR "%s is an array, not a function", p->nval SYNTAX;
1.4     ! kstailey  451:        else if (isfcn(p))
1.1       tholo     452:                ERROR "you can't define function %s more than once", p->nval SYNTAX;
                    453:        curfname = p->nval;
                    454: }
                    455:
                    456: int constnode(Node *p)
                    457: {
                    458:        return isvalue(p) && ((Cell *) (p->narg[0]))->csub == CCON;
                    459: }
                    460:
                    461: char *strnode(Node *p)
                    462: {
                    463:        return ((Cell *)(p->narg[0]))->sval;
                    464: }
                    465:
                    466: Node *notnull(Node *n)
                    467: {
                    468:        switch (n->nobj) {
                    469:        case LE: case LT: case EQ: case NE: case GT: case GE:
                    470:        case BOR: case AND: case NOT:
                    471:                return n;
                    472:        default:
                    473:                return op2(NE, n, nullnode);
                    474:        }
                    475: }
                    476:
                    477: void checkdup(Node *vl, Cell *cp)      /* check if name already in list */
                    478: {
                    479:        char *s = cp->nval;
                    480:        for ( ; vl; vl = vl->nnext) {
                    481:                if (strcmp(s, ((Cell *)(vl->narg[0]))->nval) == 0) {
                    482:                        ERROR "duplicate argument %s", s SYNTAX;
                    483:                        break;
                    484:                }
                    485:        }
                    486: }