ref: 05f6c08985c9bd522e0a938f0e90b20df3f6792d
dir: /sys/src/cmd/rc/lex.c/
#include "rc.h" #include "exec.h" #include "io.h" #include "getflags.h" #include "fns.h" int getnext(void); 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); } int future = EOF; int doprompt = 1; int inquote; int incomm; /* * Look ahead in the input stream */ int nextc(void) { if(future==EOF) future = getnext(); return future; } /* * Consume the lookahead character. */ int advance(void) { int c = nextc(); lastc = future; future = EOF; return c; } /* * read a character from the input stream */ int getnext(void) { int c; static int peekc = EOF; if(peekc!=EOF){ c = peekc; peekc = EOF; return c; } if(runq->eof) return EOF; if(doprompt) pprompt(); c = rchr(runq->cmdfd); if(!inquote && c=='\\'){ c = rchr(runq->cmdfd); if(c=='\n' && !incomm){ /* don't continue a comment */ doprompt = 1; c=' '; } else{ peekc = c; c='\\'; } } doprompt = doprompt || c=='\n' || c==EOF; if(c==EOF) runq->eof++; else if(flag['V'] || ndot>=2 && flag['v']) pchr(err, c); return c; } void pprompt(void) { var *prompt; if(runq->iflag){ pstr(err, promptstr); flush(err); if(newwdir){ char dir[4096]; int fd; if((fd=open("/dev/wdir", OWRITE))>=0){ getwd(dir, sizeof(dir)); write(fd, dir, strlen(dir)); close(fd); } newwdir = 0; } prompt = vlook("prompt"); if(prompt->val && prompt->val->next) promptstr = prompt->val->next->word; else promptstr="\t"; } runq->lineno++; doprompt = 0; } void skipwhite(void) { int c; for(;;){ c = nextc(); /* Why did this used to be if(!inquote && c=='#') ?? */ if(c=='#'){ incomm = 1; for(;;){ c = nextc(); if(c=='\n' || c==EOF) { 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(); } } int nextis(int c) { if(nextc()==c){ advance(); return 1; } return 0; } char* addtok(char *p, int val) { if(p==0) return 0; if(p==&tok[NTOK-1]){ *p = 0; yyerror("token buffer too short"); return 0; } *p++=val; return p; } char* addutf(char *p, int c) { uchar b, m; int i; p = addtok(p, c); /* 1-byte UTF runes are special */ if(onebyte(c)) return p; m = 0xc0; b = 0x80; for(i=1; i < UTFmax; i++){ if((c&m) == b) break; p = addtok(p, advance()); b = m; m = (m >> 1)|0x80; } return p; } int lastdol; /* was the last token read '$' or '$#' or '"'? */ int lastword; /* was the last token read a word or compound word terminator? */ int yylex(void) { int c, d = nextc(); char *w = tok; struct 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(lastword){ lastword = 0; if(d=='('){ advance(); strcpy(tok, "( [SUB]"); return SUB; } if(wordchr(d) || d=='\'' || d=='`' || d=='$' || d=='"'){ strcpy(tok, "^"); return '^'; } } inquote = 0; skipwhite(); switch(c = advance()){ case EOF: lastdol = 0; strcpy(tok, "EOF"); return EOF; case '$': lastdol = 1; if(nextis('#')){ strcpy(tok, "$#"); return COUNT; } if(nextis('"')){ strcpy(tok, "$\""); return '"'; } strcpy(tok, "$"); return '$'; case '&': lastdol = 0; if(nextis('&')){ skipnl(); strcpy(tok, "&&"); return ANDAND; } strcpy(tok, "&"); return '&'; case '|': lastdol = 0; if(nextis(c)){ skipnl(); strcpy(tok, "||"); return OROR; } case '<': case '>': 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 '\'': lastdol = 0; lastword = 1; 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)){ lastdol = 0; tok[0] = c; tok[1]='\0'; return c; } for(;;){ if(c=='*' || c=='[' || c=='?' || c==GLOB) w = addtok(w, GLOB); w = addutf(w, c); c = nextc(); if(lastdol?!idchr(c):!wordchr(c)) break; advance(); } lastword = 1; lastdol = 0; if(w!=0) *w='\0'; t = klook(tok); if(t->type!=WORD) lastword = 0; t->quoted = 0; yylval.tree = t; return t->type; }