diff options
Diffstat (limited to 'src/cmd/mk/lex.c')
-rw-r--r-- | src/cmd/mk/lex.c | 147 |
1 files changed, 147 insertions, 0 deletions
diff --git a/src/cmd/mk/lex.c b/src/cmd/mk/lex.c new file mode 100644 index 00000000..3ee244f1 --- /dev/null +++ b/src/cmd/mk/lex.c @@ -0,0 +1,147 @@ +#include "mk.h" + +static int bquote(Biobuf*, Bufblock*); + +/* + * Assemble a line skipping blank lines, comments, and eliding + * escaped newlines + */ +int +assline(Biobuf *bp, Bufblock *buf) +{ + int c; + int lastc; + + buf->current=buf->start; + while ((c = nextrune(bp, 1)) >= 0){ + switch(c) + { + case '\r': /* consumes CRs for Win95 */ + continue; + case '\n': + if (buf->current != buf->start) { + insert(buf, 0); + return 1; + } + break; /* skip empty lines */ + case '\\': + case '\'': + case '"': + rinsert(buf, c); + if (escapetoken(bp, buf, 1, c) == 0) + Exit(); + break; + case '`': + if (bquote(bp, buf) == 0) + Exit(); + break; + case '#': + lastc = '#'; + while ((c = Bgetc(bp)) != '\n') { + if (c < 0) + goto eof; + if(c != '\r') + lastc = c; + } + mkinline++; + if (lastc == '\\') + break; /* propagate escaped newlines??*/ + if (buf->current != buf->start) { + insert(buf, 0); + return 1; + } + break; + default: + rinsert(buf, c); + break; + } + } +eof: + insert(buf, 0); + return *buf->start != 0; +} + +/* + * assemble a back-quoted shell command into a buffer + */ +static int +bquote(Biobuf *bp, Bufblock *buf) +{ + int c, line, term; + int start; + + line = mkinline; + while((c = Bgetrune(bp)) == ' ' || c == '\t') + ; + if(c == '{'){ + term = '}'; /* rc style */ + while((c = Bgetrune(bp)) == ' ' || c == '\t') + ; + } else + term = '`'; /* sh style */ + + start = buf->current-buf->start; + for(;c > 0; c = nextrune(bp, 0)){ + if(c == term){ + insert(buf, '\n'); + insert(buf,0); + buf->current = buf->start+start; + execinit(); + execsh(0, buf->current, buf, envy); + return 1; + } + if(c == '\n') + break; + if(c == '\'' || c == '"' || c == '\\'){ + insert(buf, c); + if(!escapetoken(bp, buf, 1, c)) + return 0; + continue; + } + rinsert(buf, c); + } + SYNERR(line); + fprint(2, "missing closing %c after `\n", term); + return 0; +} + +/* + * get next character stripping escaped newlines + * the flag specifies whether escaped newlines are to be elided or + * replaced with a blank. + */ +int +nextrune(Biobuf *bp, int elide) +{ + int c, c2; + static int savec; + + if(savec){ + c = savec; + savec = 0; + return c; + } + + for (;;) { + c = Bgetrune(bp); + if (c == '\\') { + c2 = Bgetrune(bp); + if(c2 == '\r'){ + savec = c2; + c2 = Bgetrune(bp); + } + if (c2 == '\n') { + savec = 0; + mkinline++; + if (elide) + continue; + return ' '; + } + Bungetrune(bp); + } + if (c == '\n') + mkinline++; + return c; + } + return 0; +} |