ref: 931ae0cfebeb46892406efc7468636e59f8110a9
dir: /sys/src/cmd/rc/lex.c/
#include "rc.h" #include "io.h" #include "getflags.h" #include "fns.h" lexer *lex; int doprompt = 1; int nerror; int wordchr(int c) { return !strchr("\n \t#;&|^$=`'{}()<>", c) && c!=EOF; } int idchr(int c) { /* * Formerly: * return 'a'<=c && c<='z' || 'A'<=c && c<='Z' || '0'<=c && c<='9' * || c=='_' || c=='*'; */ return c>' ' && !strchr("!\"#$%&'()+,-./:;<=>?@[\\]^`{|}~", c); } lexer* newlexer(io *input, char *file) { lexer *n = new(struct lexer); n->input = input; n->file = file; n->line = 1; n->eof = 0; n->future = EOF; n->peekc = '{'; n->epilog = "}\n"; n->lastc = 0; n->inquote = 0; n->incomm = 0; n->lastword = 0; n->lastdol = 0; n->iflast = 0; n->qflag = 0; n->tok[0] = 0; return n; } void freelexer(lexer *p) { closeio(p->input); free(p->file); free(p); } /* * read a character from the input stream */ static int getnext(void) { int c; if(lex->peekc!=EOF){ c = lex->peekc; lex->peekc = EOF; return c; } if(lex->eof){ epilog: if(*lex->epilog) return *lex->epilog++; doprompt = 1; return EOF; } if(doprompt) pprompt(); c = rchr(lex->input); if(c=='\\' && !lex->inquote){ c = rchr(lex->input); if(c=='\n' && !lex->incomm){ /* don't continue a comment */ doprompt = 1; c=' '; } else{ lex->peekc = c; c='\\'; } } if(c==EOF){ lex->eof = 1; goto epilog; } else { if(c=='\n') doprompt = 1; if((!lex->qflag && flag['v']!=0) || flag['V']) pchr(err, c); } return c; } /* * Look ahead in the input stream */ static int nextc(void) { if(lex->future==EOF) lex->future = getnext(); return lex->future; } /* * Consume the lookahead character. */ static int advance(void) { int c = nextc(); lex->lastc = lex->future; lex->future = EOF; if(c == '\n') lex->line++; return c; } static void skipwhite(void) { int c; for(;;){ c = nextc(); /* Why did this used to be if(!inquote && c=='#') ?? */ if(c=='#'){ lex->incomm = 1; for(;;){ c = nextc(); if(c=='\n' || c==EOF) { lex->incomm = 0; break; } advance(); } } if(c==' ' || c=='\t') advance(); else return; } } void skipnl(void) { int c; for(;;){ skipwhite(); c = nextc(); if(c!='\n') return; advance(); } } static int nextis(int c) { if(nextc()==c){ advance(); return 1; } return 0; } static char* addtok(char *p, int val) { if(p==0) return 0; if(p==&lex->tok[NTOK-1]){ *p = 0; yyerror("token buffer too short"); return 0; } *p++=val; return p; } static char* addutf(char *p, int c) { int i, n; p = addtok(p, c); /* 1-byte UTF runes are special */ if(onebyte(c)) return p; if(twobyte(c)) n = 2; else if(threebyte(c)) n = 3; else n = 4; for(i = 1; i < n; i++) { c = nextc(); if(c == EOF || !xbyte(c)) break; p = addtok(p, advance()); } return p; } int yylex(void) { int glob, c, d = nextc(); char *tok = lex->tok; char *w = tok; tree *t; yylval.tree = 0; /* * Embarassing sneakiness: if the last token read was a quoted or unquoted * WORD then we alter the meaning of what follows. If the next character * is `(', we return SUB (a subscript paren) and consume the `('. Otherwise, * if the next character is the first character of a simple or compound word, * we insert a `^' before it. */ if(lex->lastword){ lex->lastword = 0; if(d=='('){ advance(); strcpy(tok, "( [SUB]"); return SUB; } if(wordchr(d) || d=='\'' || d=='`' || d=='$' || d=='"'){ strcpy(tok, "^"); return '^'; } } lex->inquote = 0; skipwhite(); switch(c = advance()){ case EOF: lex->lastdol = 0; strcpy(tok, "EOF"); return EOF; case '$': lex->lastdol = 1; if(nextis('#')){ strcpy(tok, "$#"); return COUNT; } if(nextis('"')){ strcpy(tok, "$\""); return '"'; } strcpy(tok, "$"); return '$'; case '&': lex->lastdol = 0; if(nextis('&')){ skipnl(); strcpy(tok, "&&"); return ANDAND; } strcpy(tok, "&"); return '&'; case '|': lex->lastdol = 0; if(nextis(c)){ skipnl(); strcpy(tok, "||"); return OROR; } case '<': case '>': lex->lastdol = 0; /* * funny redirection tokens: * redir: arrow | arrow '[' fd ']' * arrow: '<' | '<<' | '>' | '>>' | '|' * fd: digit | digit '=' | digit '=' digit * digit: '0'|'1'|'2'|'3'|'4'|'5'|'6'|'7'|'8'|'9' * some possibilities are nonsensical and get a message. */ *w++=c; t = newtree(); switch(c){ case '|': t->type = PIPE; t->fd0 = 1; t->fd1 = 0; break; case '>': t->type = REDIR; if(nextis(c)){ t->rtype = APPEND; *w++=c; } else t->rtype = WRITE; t->fd0 = 1; break; case '<': t->type = REDIR; if(nextis(c)){ t->rtype = HERE; *w++=c; } else if (nextis('>')){ t->rtype = RDWR; *w++=c; } else t->rtype = READ; t->fd0 = 0; break; } if(nextis('[')){ *w++='['; c = advance(); *w++=c; if(c<'0' || '9'<c){ RedirErr: *w = 0; yyerror(t->type==PIPE?"pipe syntax" :"redirection syntax"); return EOF; } t->fd0 = 0; do{ t->fd0 = t->fd0*10+c-'0'; *w++=c; c = advance(); }while('0'<=c && c<='9'); if(c=='='){ *w++='='; if(t->type==REDIR) t->type = DUP; c = advance(); if('0'<=c && c<='9'){ t->rtype = DUPFD; t->fd1 = t->fd0; t->fd0 = 0; do{ t->fd0 = t->fd0*10+c-'0'; *w++=c; c = advance(); }while('0'<=c && c<='9'); } else{ if(t->type==PIPE) goto RedirErr; t->rtype = CLOSE; } } if(c!=']' || t->type==DUP && (t->rtype==HERE || t->rtype==APPEND)) goto RedirErr; *w++=']'; } *w='\0'; yylval.tree = t; if(t->type==PIPE) skipnl(); return t->type; case '\'': lex->lastdol = 0; lex->lastword = 1; lex->inquote = 1; for(;;){ c = advance(); if(c==EOF) break; if(c=='\''){ if(nextc()!='\'') break; advance(); } w = addutf(w, c); } if(w!=0) *w='\0'; t = token(tok, WORD); t->quoted = 1; yylval.tree = t; return t->type; } if(!wordchr(c)){ lex->lastdol = 0; tok[0] = c; tok[1]='\0'; return c; } glob = 0; for(;;){ if(c=='*' || c=='[' || c=='?' || c==GLOB){ glob = 1; w = addtok(w, GLOB); } w = addutf(w, c); c = nextc(); if(lex->lastdol?!idchr(c):!wordchr(c)) break; advance(); } lex->lastword = 1; lex->lastdol = 0; if(w!=0) *w='\0'; t = klook(tok); if(t->type!=WORD) lex->lastword = 0; else t->glob = glob; t->quoted = 0; yylval.tree = t; return t->type; } void yyerror(char *m) { pfln(err, lex->file, lex->line); pstr(err, ": "); if(lex->tok[0] && lex->tok[0]!='\n') pfmt(err, "token %q: ", lex->tok); pfmt(err, "%s\n", m); flushio(err); lex->lastword = 0; lex->lastdol = 0; while(lex->lastc!='\n' && lex->lastc!=EOF) advance(); nerror++; setstatus(m); }