commit 47d4646eebac34c0b94951cfcf1b81ed2ca513e1 from: Russ Cox date: Tue May 05 03:41:15 2020 UTC rc: add recursive descent parser The old yacc-based parser is available with the -Y flag, which will probably be removed at some point. The new -D flag dumps a parse tree of the input, without executing it. This allows comparing the output of rc -D and rc -DY on different scripts to see that the two parsers behave the same. The rc paper ends by saying: It is remarkable that in the four most recent editions of the UNIX system programmer’s manual the Bourne shell grammar described in the manual page does not admit the command who|wc. This is surely an oversight, but it suggests something darker: nobody really knows what the Bourne shell’s grammar is. Even examination of the source code is little help. The parser is implemented by recursive descent, but the routines corresponding to the syntactic categories all have a flag argument that subtly changes their operation depending on the context. Rc’s parser is implemented using yacc, so I can say precisely what the grammar is. The new recursive descent parser here has no such flags. It is a straightforward translation of the yacc. The new parser will make it easier to handle free carats in more generality as well as potentially allow the use of unquoted = as a word character. Going through this exercise has highlighted a few dark corners here as well. For example, I was surprised to find that x >f | y >f x | y are different commands (the latter redirects y's output). It is similarly surprising that a=b x | y sets a during the execution of y. It is also a bit counter-intuitive x | y | z x | if(c) y | z are not both 3-phase pipelines. These are certainly not things we should change, but they are not entirely obvious from the man page description, undercutting the quoted claim a bit. On the other hand, who | wc is clearly accepted by the grammar in the manual page, and the new parser still handles that test case. commit - c1c1b5267fd5e14be531a4b22ed0124b35d427cb commit + 47d4646eebac34c0b94951cfcf1b81ed2ca513e1 blob - eeaa3ed88d9a2d7da4b7753818d790027767624a blob + 208476ae3e65455294299a362110f77e00572879 --- src/cmd/rc/code.c +++ src/cmd/rc/code.c @@ -41,6 +41,16 @@ stuffdot(int a) int compile(tree *t) { + if(flag['D']) { + struct io *s; + s = openstr(); + pfmt(s, "compile: %u\n", t); + write(2, s->strp, strlen(s->strp)); + closeio(s); + if(eflagok) // made it out of rcmain - stop executing commands, just print them + t = nil; + } + ncode = 100; codebuf = (code *)emalloc(ncode*sizeof codebuf[0]); codep = 0; blob - /dev/null blob + cccc40585e853313919e5126dcc42fb64de87a41 (mode 755) --- /dev/null +++ src/cmd/rc/checkparse @@ -0,0 +1,14 @@ +#!/bin/bash + +files="$@" +if [ $# = 0 ]; then + files=$(echo ./test.rc; + grep -l '^#!/usr/local/plan9/bin/rc' /usr/local/plan9/bin/{*,*/*} 2>/dev/null; + grep -l '^#!/bin/rc' $HOME/pub/plan9/rc/bin/{*,*/*} 2>/dev/null) +fi + +for i in $files +do + echo '#' $i + diff <(./o.rc -DY $i 2>&1) <(./o.rc -D $i 2>&1) +done blob - 172acfa3e008063edfbfa1a72ea424cdf0e07ae1 blob + 0320976a2d0ee0e881b7e95931d07494d16cf7cb --- src/cmd/rc/exec.c +++ src/cmd/rc/exec.c @@ -139,7 +139,7 @@ main(int argc, char *argv[]) /* needed for rcmain later */ putenv("PLAN9", unsharp("#9")); - argc = getflags(argc, argv, "SsrdiIlxepvVc:1m:1[command]", 1); + argc = getflags(argc, argv, "DSYsrdiIlxepvVc:1m:1[command]", 1); if(argc==-1) usage("[file [arg ...]]"); if(argv[0][0]=='-') @@ -901,7 +901,7 @@ Xrdcmds(void) promptstr="% "; } Noerror(); - if(yyparse()){ + if((flag['Y'] ? yyparse : parse)()){ if(!p->iflag || p->eof && !Eintr()){ if(p->cmdfile) efree(p->cmdfile); blob - c4d201dcb9ba4a37913d86d3b5cc0995da9e3095 blob + 5721d6175721c609ae1863740a79304da3d16610 --- src/cmd/rc/fns.h +++ src/cmd/rc/fns.h @@ -65,3 +65,4 @@ int wordchr(int); void yyerror(char*); int yylex(void); int yyparse(void); +int parse(void); blob - bb8af4ab4d4ac4c97043867f824399a163ce235a blob + c2e9d7b4698e08665a504ed1721f48523e93f8b2 --- src/cmd/rc/io.c +++ src/cmd/rc/io.c @@ -44,8 +44,11 @@ pfmt(io *f, char *fmt, ...) pstr(f, va_arg(ap, char *)); break; case 't': - pcmd(f, va_arg(ap, struct tree *)); + pcmd(f, va_arg(ap, tree *)); break; + case 'u': + pcmdu(f, va_arg(ap, tree *)); + break; case 'v': pval(f, va_arg(ap, struct word *)); break; blob - 21cc6b8e8fdfc44b5c7f0727fc09ea74868eeb61 blob + 6c75cc5bc6eed784e6e7d84ad35df65cdf0d879d --- src/cmd/rc/io.h +++ src/cmd/rc/io.h @@ -25,6 +25,7 @@ void pquo(io*, char*); void pwrd(io*, char*); void pstr(io*, char*); void pcmd(io*, tree*); +void pcmdu(io*, tree*); void pval(io*, word*); void pfnc(io*, thread*); void pfmt(io*, char*, ...); blob - 973ddee8d97485511025a8935009508f695dbf20 blob + 0bdbbb4b8845a68489cbbfd841817cf78532f8a2 --- src/cmd/rc/lex.c +++ src/cmd/rc/lex.c @@ -188,7 +188,7 @@ yylex(void) { int c, d = nextc(); char *w = tok; - struct tree *t; + tree *t; yylval.tree = 0; /* * Embarassing sneakiness: if the last token read was a quoted or unquoted @@ -331,6 +331,11 @@ yylex(void) yylval.tree = t; if(t->type==PIPE) skipnl(); + if(t->type==REDIR) { + skipwhite(); + if(nextc() == '{') + t->type = REDIRW; + } return t->type; case '\'': lastdol = 0; blob - 79b407f88d0790e0cf76ebd14c4ebe4214fccd8c blob + c1e77aef5e23182219a7f5680709a0584380536b --- src/cmd/rc/mkfile +++ src/cmd/rc/mkfile @@ -10,6 +10,7 @@ OFILES=\ here.$O\ io.$O\ lex.$O\ + parse.$O\ pcmd.$O\ pfnc.$O\ simple.$O\ blob - 8caf60a28cc0a0ff2babe23be79919f0942304c1 blob + 26bd883bcd545cc44c7ba45c37ab71ac92bd69e5 --- src/cmd/rc/pcmd.c +++ src/cmd/rc/pcmd.c @@ -145,3 +145,118 @@ pcmd(io *f, tree *t) break; } } + +void +pcmdu(io *f, tree *t) /* unambiguous */ +{ + if(t==0) { + pfmt(f, ""); + return; + } + + switch(t->type){ + default: pfmt(f, "(bad %d %p %p %p)", t->type, c0, c1, c2); + break; + case '$': pfmt(f, "($ %u)", c0); + break; + case '"': pfmt(f, "($\" %u)", c0); + break; + case '&': pfmt(f, "(& %u)", c0); + break; + case '^': pfmt(f, "(^ %u %u)", c0, c1); + break; + case '`': pfmt(f, "(` %u)", c0); + break; + case ANDAND: pfmt(f, "(&& %u %u)", c0, c1); + break; + case BANG: pfmt(f, "(! %u)", c0); + break; + case BRACE: pfmt(f, "(brace %u)", c0); + break; + case COUNT: pfmt(f, "($# %u)", c0); + break; + case FN: pfmt(f, "(fn %u %u)", c0, c1); + break; + case IF: pfmt(f, "(if %u %u)", c0, c1); + break; + case NOT: pfmt(f, "(if not %u)", c0); + break; + case OROR: pfmt(f, "(|| %u %u)", c0, c1); + break; + case PCMD: + case PAREN: pfmt(f, "(paren %u)", c0); + break; + case SUB: pfmt(f, "($sub %u %u)", c0, c1); + break; + case SIMPLE: pfmt(f, "(simple %u)", c0); + break; + case SUBSHELL: pfmt(f, "(@ %u)", c0); + break; + case SWITCH: pfmt(f, "(switch %u %u)", c0, c1); + break; + case TWIDDLE: pfmt(f, "(~ %u %u)", c0, c1); + break; + case WHILE: pfmt(f, "(while %u %u)", c0, c1); + break; + case ARGLIST: + pfmt(f, "(arglist %u %u)", c0, c1); + break; + case ';': + pfmt(f, "(; %u %u)", c0, c1); + break; + case WORDS: + pfmt(f, "(words %u %u)", c0, c1); + break; + case FOR: + pfmt(f, "(for %u %u %u)", c0, c1, c2); + break; + case WORD: + if(t->quoted) + pfmt(f, "%Q", t->str); + else pdeglob(f, t->str); + break; + case DUP: + if(t->rtype==DUPFD) + pfmt(f, "(>[%d=%d]", t->fd1, t->fd0); /* yes, fd1, then fd0; read lex.c */ + else + pfmt(f, "(>[%d=]", t->fd0); /*)*/ + pfmt(f, " %u)", c1); + break; + case PIPEFD: + case REDIR: + pfmt(f, "("); + switch(t->rtype){ + case HERE: + pchr(f, '<'); + case READ: + case RDWR: + pchr(f, '<'); + if(t->rtype==RDWR) + pchr(f, '>'); + if(t->fd0!=0) + pfmt(f, "[%d]", t->fd0); + break; + case APPEND: + pchr(f, '>'); + case WRITE: + pchr(f, '>'); + if(t->fd0!=1) + pfmt(f, "[%d]", t->fd0); + break; + } + pfmt(f, "%u %u)", c0, c1); + break; + case '=': + pfmt(f, "(%u=%u %u)", c0, c1, c2); + break; + case PIPE: + pfmt(f, "(|"); + if(t->fd1==0){ + if(t->fd0!=1) + pfmt(f, "[%d]", t->fd0); + } + else pfmt(f, "[%d=%d]", t->fd0, t->fd1); + pfmt(f, " %u %u", c0, c1); + break; + } +} blob - /dev/null blob + 6071bdffefb01f52f6fda74521d977abb3f6992d (mode 644) --- /dev/null +++ src/cmd/rc/parse.c @@ -0,0 +1,532 @@ +#include "rc.h" +#include "io.h" +#include "fns.h" + +static tree* body(int tok, int *ptok); +static tree* brace(int tok); +static tree* cmd(int tok, int *ptok); +static tree* cmd2(int tok, int *ptok); +static tree* cmd3(int tok, int *ptok); +static tree* cmd4(int tok, int *ptok); +static tree* cmds(int tok, int *ptok, int nlok); +static tree* epilog(int tok, int *ptok); +static int iswordtok(int tok); +static tree* line(int tok, int *ptok); +static tree* paren(int tok); +static tree* yyredir(int tok, int *ptok); +static tree* yyword(int tok, int *ptok); +static tree* word1(int tok, int *ptok); +static tree* words(int tok, int *ptok); + +static jmp_buf yyjmp; + +static void +syntax(int tok) +{ + char buf[100]; + snprint(buf, sizeof buf, "syntax error %d", tok); + yyerror(buf); + longjmp(yyjmp, 1); +} + +int +parse(void) +{ + tree *t; + int tok; + + if(setjmp(yyjmp)) + return 1; + + // rc: { return 1;} + // | line '\n' {return !compile($1);} + + tok = yylex(); + if(tok == EOF) + return 1; + t = line(tok, &tok); + if(tok != '\n') + yyerror("missing newline at end of line"); + yylval.tree = t; + return !compile(t); +} + +static tree* +line(int tok, int *ptok) +{ + return cmds(tok, ptok, 0); +} + +static tree* +body(int tok, int *ptok) +{ + return cmds(tok, ptok, 1); +} + +static tree* +cmds(int tok, int *ptok, int nlok) +{ + tree *t, **last, *t2; + + // line: cmd + // | cmdsa line {$$=tree2(';', $1, $2);} + // cmdsa: cmd ';' + // | cmd '&' {$$=tree1('&', $1);} + + // body: cmd + // | cmdsan body {$$=tree2(';', $1, $2);} + // cmdsan: cmdsa + // | cmd '\n' + + t = nil; + last = nil; + for(;;) { + t2 = cmd(tok, &tok); + if(tok == '&') + t2 = tree1('&', t2); + if(t2 != nil) { + // slot into list t + if(last == nil) { + t = t2; + last = &t; + } else { + *last = tree2(';', *last, t2); + last = &(*last)->child[1]; + } + } + if(tok != ';' && tok != '&' && (!nlok || tok != '\n')) + break; + tok = yylex(); + } + *ptok = tok; + return t; +} + +static tree* +brace(int tok) +{ + tree *t; + + // brace: '{' body '}' {$$=tree1(BRACE, $2);} + + if(tok != '{') + syntax(tok); + t = body(yylex(), &tok); + if(tok != '}') + syntax(tok); + return tree1(BRACE, t); +} + +static tree* +paren(int tok) +{ + tree *t; + + // paren: '(' body ')' {$$=tree1(PCMD, $2);} + + if(tok != '(') + syntax(tok); + t = body(yylex(), &tok); + if(tok != ')') + syntax(tok); + return tree1(PCMD, t); +} + +static tree* +epilog(int tok, int *ptok) +{ + tree *t, *r; + + // epilog: {$$=0;} + // | redir epilog {$$=mung2($1, $1->child[0], $2);} + + if(tok != REDIR && tok != DUP) { + *ptok = tok; + return nil; + } + + r = yyredir(tok, &tok); + t = epilog(tok, &tok); + *ptok = tok; + return mung2(r, r->child[0], t); +} + +static tree* +yyredir(int tok, int *ptok) +{ + tree *r, *w; + + // redir: REDIR word {$$=mung1($1, $1->rtype==HERE?heredoc($2):$2);} + // | DUP + + switch(tok) { + default: + syntax(tok); + case DUP: + r = yylval.tree; + *ptok = yylex(); + break; + case REDIR: + r = yylval.tree; + w = yyword(yylex(), ptok); + r = mung1(r, r->rtype==HERE?heredoc(w):w); + break; + } + return r; +} + +static tree* +cmd(int tok, int *ptok) +{ + tree *t1, *t2, *t3, *t4; + + switch(tok) { + default: + return cmd2(tok, ptok); + + case IF: + // | IF paren {skipnl();} cmd {$$=mung2($1, $2, $4);} + // | IF NOT {skipnl();} cmd {$$=mung1($2, $4);} + t1 = yylval.tree; + tok = yylex(); + if(tok == NOT) { + t1 = yylval.tree; + skipnl(); + t2 = cmd(yylex(), ptok); + return mung1(t1, t2); + } + t2 = paren(tok); + skipnl(); + t3 = cmd(yylex(), ptok); + return mung2(t1, t2, t3); + + case FOR: + // | FOR '(' word IN words ')' {skipnl();} cmd + // {$$=mung3($1, $3, $5 ? $5 : tree1(PAREN, $5), $8);} + // | FOR '(' word ')' {skipnl();} cmd + // {$$=mung3($1, $3, (tree *)0, $6);} + t1 = yylval.tree; + tok = yylex(); + if(tok != '(') + syntax(tok); + t2 = yyword(yylex(), &tok); + switch(tok) { + default: + syntax(tok); + case ')': + t3 = nil; + break; + case IN: + t3 = words(yylex(), &tok); + if(t3 == nil) + t3 = tree1(PAREN, nil); + if(tok != ')') + syntax(tok); + break; + } + skipnl(); + t4 = cmd(yylex(), ptok); + return mung3(t1, t2, t3, t4); + + case WHILE: + // | WHILE paren {skipnl();} cmd + // {$$=mung2($1, $2, $4);} + t1 = yylval.tree; + t2 = paren(yylex()); + skipnl(); + t3 = cmd(yylex(), ptok); + return mung2(t1, t2, t3); + + case SWITCH: + // | SWITCH word {skipnl();} brace + // {$$=tree2(SWITCH, $2, $4);} + t1 = yyword(yylex(), &tok); + while(tok == '\n') + tok = yylex(); + t2 = brace(tok); + *ptok = yylex(); + return tree2(SWITCH, t1, t2); + } +} + +static tree* +cmd2(int tok, int *ptok) +{ + int op; + tree *t1, *t2; + + // | cmd ANDAND cmd {$$=tree2(ANDAND, $1, $3);} + // | cmd OROR cmd {$$=tree2(OROR, $1, $3);} + + t1 = cmd3(tok, &tok); + while(tok == ANDAND || tok == OROR) { + op = tok; + t2 = cmd3(yylex(), &tok); + t1 = tree2(op, t1, t2); + } + *ptok = tok; + return t1; +} + +static tree* +cmd3(int tok, int *ptok) +{ + tree *t1, *t2, *t3; + + // | cmd PIPE cmd {$$=mung2($2, $1, $3);} + t1 = cmd4(tok, &tok); + while(tok == PIPE) { + t2 = yylval.tree; + t3 = cmd4(yylex(), &tok); + t1 = mung2(t2, t1, t3); + } + *ptok = tok; + return t1; +} + +static tree* +cmd4(int tok, int *ptok) +{ + tree *t1, *t2, *t3; + + switch(tok) { + case ';': + case '&': + case '\n': + *ptok = tok; + return nil; + + case IF: + case FOR: + case SWITCH: + case WHILE: + // Note: cmd: a && for(x) y && b is a && {for (x) {y && b}}. + return cmd(tok, ptok); + + case FN: + // | FN words brace {$$=tree2(FN, $2, $3);} + // | FN words {$$=tree1(FN, $2);} + t1 = words(yylex(), &tok); + if(tok != '{') { + *ptok = tok; + return tree1(FN, t1); + } + t2 = brace(tok); + *ptok = yylex(); + return tree2(FN, t1, t2); + + case TWIDDLE: + // | TWIDDLE word words {$$=mung2($1, $2, $3);} + t1 = yylval.tree; + t2 = yyword(yylex(), &tok); + t3 = words(tok, ptok); + return mung2(t1, t2, t3); + + case BANG: + case SUBSHELL: + // | BANG cmd {$$=mung1($1, $2);} + // | SUBSHELL cmd {$$=mung1($1, $2);} + // Note: cmd3: ! x | y is !{x | y} not {!x} | y. + t1 = yylval.tree; + return mung1(t1, cmd3(yylex(), ptok)); + + case REDIR: + case DUP: + // | redir cmd %prec BANG {$$=mung2($1, $1->child[0], $2);} + // Note: cmd3: {>x echo a | tr a-z A-Z} writes A to x. + t1 = yyredir(tok, &tok); + t2 = cmd3(tok, ptok); + return mung2(t1, t1->child[0], t2); + + case '{': + // | brace epilog {$$=epimung($1, $2);} + t1 = brace(tok); + tok = yylex(); + t2 = epilog(tok, ptok); + return epimung(t1, t2); + } + + if(!iswordtok(tok)) { + *ptok = tok; + return nil; + } + + // cmd: ... + // | simple {$$=simplemung($1);} + // | assign cmd %prec BANG {$$=mung3($1, $1->child[0], $1->child[1], $2);} + // assign: first '=' word {$$=tree2('=', $1, $3);} + // Note: first is same as word except for disallowing all the leading keywords, + // but all those keywords have been picked off in the switch above. + // Except NOT, but disallowing that in yacc was likely a mistake anyway: + // there's no ambiguity in not=1 or not x y z. + t1 = yyword(tok, &tok); + if(tok == '=') { + // assignment + // Note: cmd3: {x=1 true | echo $x} echoes 1. + t1 = tree2('=', t1, yyword(yylex(), &tok)); + t2 = cmd3(tok, ptok); + return mung3(t1, t1->child[0], t1->child[1], t2); + } + + // simple: first + // | simple word {$$=tree2(ARGLIST, $1, $2);} + // | simple redir {$$=tree2(ARGLIST, $1, $2);} + for(;;) { + if(tok == REDIR || tok == DUP) { + t1 = tree2(ARGLIST, t1, yyredir(tok, &tok)); + } else if(iswordtok(tok)) { + t1 = tree2(ARGLIST, t1, yyword(tok, &tok)); + } else { + break; + } + } + *ptok = tok; + return simplemung(t1); +} + +static tree* +words(int tok, int *ptok) +{ + tree *t; + + // words: {$$=(tree*)0;} + // | words word {$$=tree2(WORDS, $1, $2);} + + t = nil; + while(iswordtok(tok)) + t = tree2(WORDS, t, yyword(tok, &tok)); + *ptok = tok; + return t; +} + +static tree* +yyword(int tok, int *ptok) +{ + tree *t; + + // word: keyword {lastword=1; $1->type=WORD;} + // | comword + // | word '^' word {$$=tree2('^', $1, $3);} + // comword: '$' word {$$=tree1('$', $2);} + // | '$' word SUB words ')' {$$=tree2(SUB, $2, $4);} + // | '"' word {$$=tree1('"', $2);} + // | COUNT word {$$=tree1(COUNT, $2);} + // | WORD + // | '`' brace {$$=tree1('`', $2);} + // | '(' words ')' {$$=tree1(PAREN, $2);} + // | REDIR brace {$$=mung1($1, $2); $$->type=PIPEFD;} + // keyword: FOR|IN|WHILE|IF|NOT|TWIDDLE|BANG|SUBSHELL|SWITCH|FN + // + // factored into: + // + // word: word1 + // | word '^' word1 + // + // word1: keyword | comword + + t = word1(tok, &tok); + while(tok == '^') + t = tree2('^', t, word1(yylex(), &tok)); + *ptok = tok; + return t; +} + +static tree* +word1(int tok, int *ptok) +{ + tree *w, *sub, *t; + + switch(tok) { + default: + syntax(tok); + + case WORD: + case FOR: + case IN: + case WHILE: + case IF: + case NOT: + case TWIDDLE: + case BANG: + case SUBSHELL: + case SWITCH: + case FN: + // | WORD + // keyword: FOR|IN|WHILE|IF|NOT|TWIDDLE|BANG|SUBSHELL|SWITCH|FN + t = yylval.tree; + t->type = WORD; + lastword = 1; + *ptok = yylex(); + return t; + + case '$': + // comword: '$' word1 {$$=tree1('$', $2);} + // | '$' word1 SUB words ')' {$$=tree2(SUB, $2, $4);} + w = word1(yylex(), &tok); + if(tok == SUB) { + sub = words(yylex(), &tok); + if(tok != ')') + syntax(tok); + *ptok = yylex(); + return tree2(SUB, w, sub); + } + *ptok = tok; + return tree1('$', w); + + case '"': + // | '"' word1 {$$=tree1('"', $2);} + return tree1('"', word1(yylex(), ptok)); + + case COUNT: + // | COUNT word1 {$$=tree1(COUNT, $2);} + return tree1(COUNT, word1(yylex(), ptok)); + + case '`': + // | '`' brace {$$=tree1('`', $2);} + t = tree1('`', brace(yylex())); + *ptok = yylex(); + return t; + + case '(': + // | '(' words ')' {$$=tree1(PAREN, $2);} + t = tree1(PAREN, words(yylex(), &tok)); + if(tok != ')') + syntax(tok); + *ptok = yylex(); + return t; + + case REDIRW: + // | REDIRW brace {$$=mung1($1, $2); $$->type=PIPEFD;} + t = yylval.tree; + t = mung1(t, brace(yylex())); + t->type = PIPEFD; + *ptok = yylex(); + return t; + } +} + +static int +iswordtok(int tok) +{ + switch(tok) { + case FOR: + case IN: + case WHILE: + case IF: + case NOT: + case TWIDDLE: + case BANG: + case SUBSHELL: + case SWITCH: + case FN: + case '$': + case '"': + case COUNT: + case WORD: + case '`': + case '(': + case REDIRW: + return 1; + } + return 0; +} blob - d587227ade0364876fed9ceca7296fc6b6188cfa blob + a7d78f6fcf4dc6b5192df66267a0bd718c98730a --- src/cmd/rc/simple.c +++ src/cmd/rc/simple.c @@ -322,6 +322,7 @@ execdot(void) static int first = 1; char file[512]; word *path; + if(first){ dotcmds[0].i = 1; dotcmds[1].f = Xmark; blob - c7de3531385d2618b2a080252c850c3f21633e4e blob + 5c98ef80c8b00edbc894857b552b5e300552f3a0 --- src/cmd/rc/syn.y +++ src/cmd/rc/syn.y @@ -1,5 +1,5 @@ %term FOR IN WHILE IF NOT TWIDDLE BANG SUBSHELL SWITCH FN -%term WORD REDIR DUP PIPE SUB +%term WORD REDIR REDIRW DUP PIPE SUB %term SIMPLE ARGLIST WORDS BRACE PAREN PCMD PIPEFD /* not used in syntax */ /* operator priorities -- lowest first */ %left IF WHILE FOR SWITCH ')' NOT @@ -19,7 +19,7 @@ %type line paren brace body cmdsa cmdsan assign epilog redir %type cmd simple first word comword keyword words %type NOT FOR IN WHILE IF TWIDDLE BANG SUBSHELL SWITCH FN -%type WORD REDIR DUP PIPE +%type WORD REDIR REDIRW DUP PIPE %% rc: { return 1;} | line '\n' {return !compile($1);} @@ -45,7 +45,7 @@ cmd: {$$=0;} | IF NOT {skipnl();} cmd {$$=mung1($2, $4);} | FOR '(' word IN words ')' {skipnl();} cmd /* - * if ``words'' is nil, we need a tree element to distinguish between + * if ``words'' is nil, we need a tree element to distinguish between * for(i in ) and for(i), the former being a loop over the empty set * and the latter being the implicit argument loop. so if $5 is nil * (the empty set), we represent it as "()". don't parenthesize non-nil @@ -73,7 +73,7 @@ cmd: {$$=0;} simple: first | simple word {$$=tree2(ARGLIST, $1, $2);} | simple redir {$$=tree2(ARGLIST, $1, $2);} -first: comword +first: comword | first '^' word {$$=tree2('^', $1, $3);} word: keyword {lastword=1; $1->type=WORD;} | comword @@ -85,7 +85,7 @@ comword: '$' word {$$=tree1('$', $2);} | WORD | '`' brace {$$=tree1('`', $2);} | '(' words ')' {$$=tree1(PAREN, $2);} -| REDIR brace {$$=mung1($1, $2); $$->type=PIPEFD;} +| REDIRW brace {$$=mung1($1, $2); $$->type=PIPEFD;} keyword: FOR|IN|WHILE|IF|NOT|TWIDDLE|BANG|SUBSHELL|SWITCH|FN words: {$$=(struct tree*)0;} | words word {$$=tree2(WORDS, $1, $2);} blob - /dev/null blob + 8cb11e0f7954cb8cf3493f0a328917fbe95f154b (mode 644) --- /dev/null +++ src/cmd/rc/test.rc @@ -0,0 +1,38 @@ +# test for parser + +{a; b; c} +x=y a && b || c +x=y a | b | c +x=y for(i) a | b +>x for(i) a | b +>x a || b && c +a >x || b && c +a | for(i) b | c +fn x {y; z} | b && c +if (x) y +if not z +`{} >x >[1=2]y >[3=] z