diff options
author | Larry Wall <larry@wall.org> | 1989-10-18 00:00:00 +0000 |
---|---|---|
committer | Larry Wall <larry@wall.org> | 1989-10-18 00:00:00 +0000 |
commit | a687059cbaf2c6fdccb5e0fae2aee80ec15625a8 (patch) | |
tree | 674c8533b7bd942204f23782934c72f8624dd308 /regcomp.h | |
parent | 13281fa4f8547e0eb31d1986b865d9b7ec7d0dcc (diff) | |
download | perl-a687059cbaf2c6fdccb5e0fae2aee80ec15625a8.tar.gz |
perl 3.0: (no announcement message available)perl-3.000
A few of the new features: (18 Oct)
* Perl can now handle binary data correctly and has functions to pack and unpack binary structures into arrays or lists. You can now do arbitrary ioctl functions.
* You can now pass things to subroutines by reference.
* Debugger enhancements.
* An array or associative array may now appear in a local() list.
* Array values may now be interpolated into strings.
* Subroutine names are now distinguished by prefixing with &. You can call subroutines without using do, and without passing any argument list at all.
* You can use the new -u switch to cause perl to dump core so that you can run undump and produce a binary executable image. Alternately you can use the "dump" operator after initializing any variables and such.
* You can now chop lists.
* Perl now uses /bin/csh to do filename globbing, if available. This means that filenames with spaces or other strangenesses work right.
* New functions: mkdir and rmdir, getppid, getpgrp and setpgrp, getpriority and setpriority, chroot, ioctl and fcntl, flock, readlink, lstat, rindex, pack and unpack, read, warn, dbmopen and dbmclose, dump, reverse, defined, undef.
Diffstat (limited to 'regcomp.h')
-rw-r--r-- | regcomp.h | 185 |
1 files changed, 185 insertions, 0 deletions
diff --git a/regcomp.h b/regcomp.h new file mode 100644 index 0000000000..c4c6520262 --- /dev/null +++ b/regcomp.h @@ -0,0 +1,185 @@ +/* $Header: regcomp.h,v 3.0 89/10/18 15:22:39 lwall Locked $ + * + * $Log: regcomp.h,v $ + * Revision 3.0 89/10/18 15:22:39 lwall + * 3.0 baseline + * + */ + +/* + * The "internal use only" fields in regexp.h are present to pass info from + * compile to execute that permits the execute phase to run lots faster on + * simple cases. They are: + * + * regstart str that must begin a match; Nullch if none obvious + * reganch is the match anchored (at beginning-of-line only)? + * regmust string (pointer into program) that match must include, or NULL + * [regmust changed to STR* for bminstr()--law] + * regmlen length of regmust string + * [regmlen not used currently] + * + * Regstart and reganch permit very fast decisions on suitable starting points + * for a match, cutting down the work a lot. Regmust permits fast rejection + * of lines that cannot possibly match. The regmust tests are costly enough + * that regcomp() supplies a regmust only if the r.e. contains something + * potentially expensive (at present, the only such thing detected is * or + + * at the start of the r.e., which can involve a lot of backup). Regmlen is + * supplied because the test in regexec() needs it and regcomp() is computing + * it anyway. + * [regmust is now supplied always. The tests that use regmust have a + * heuristic that disables the test if it usually matches.] + * + * [In fact, we now use regmust in many cases to locate where the search + * starts in the string, so if regback is >= 0, the regmust search is never + * wasted effort. The regback variable says how many characters back from + * where regmust matched is the earliest possible start of the match. + * For instance, /[a-z].foo/ has a regmust of 'foo' and a regback of 2.] + */ + +/* + * Structure for regexp "program". This is essentially a linear encoding + * of a nondeterministic finite-state machine (aka syntax charts or + * "railroad normal form" in parsing technology). Each node is an opcode + * plus a "next" pointer, possibly plus an operand. "Next" pointers of + * all nodes except BRANCH implement concatenation; a "next" pointer with + * a BRANCH on both ends of it is connecting two alternatives. (Here we + * have one of the subtle syntax dependencies: an individual BRANCH (as + * opposed to a collection of them) is never concatenated with anything + * because of operator precedence.) The operand of some types of node is + * a literal string; for others, it is a node leading into a sub-FSM. In + * particular, the operand of a BRANCH node is the first node of the branch. + * (NB this is *not* a tree structure: the tail of the branch connects + * to the thing following the set of BRANCHes.) The opcodes are: + */ + +/* definition number opnd? meaning */ +#define END 0 /* no End of program. */ +#define BOL 1 /* no Match "" at beginning of line. */ +#define EOL 2 /* no Match "" at end of line. */ +#define ANY 3 /* no Match any one character. */ +#define ANYOF 4 /* str Match any character in this string. */ +#define ANYBUT 5 /* str Match any character not in this string. */ +#define BRANCH 6 /* node Match this alternative, or the next... */ +#define BACK 7 /* no Match "", "next" ptr points backward. */ +#define EXACTLY 8 /* str Match this string (preceded by length). */ +#define NOTHING 9 /* no Match empty string. */ +#define STAR 10 /* node Match this (simple) thing 0 or more times. */ +#define PLUS 11 /* node Match this (simple) thing 1 or more times. */ +#define ALNUM 12 /* no Match any alphanumeric character */ +#define NALNUM 13 /* no Match any non-alphanumeric character */ +#define BOUND 14 /* no Match "" at any word boundary */ +#define NBOUND 15 /* no Match "" at any word non-boundary */ +#define SPACE 16 /* no Match any whitespace character */ +#define NSPACE 17 /* no Match any non-whitespace character */ +#define DIGIT 18 /* no Match any numeric character */ +#define NDIGIT 19 /* no Match any non-numeric character */ +#define REF 20 /* no Match some already matched string */ +#define OPEN 30 /* no Mark this point in input as start of #n. */ + /* OPEN+1 is number 1, etc. */ +#define CLOSE 40 /* no Analogous to OPEN. */ +/* CLOSE must be last one! see regmust finder */ + +/* + * Opcode notes: + * + * BRANCH The set of branches constituting a single choice are hooked + * together with their "next" pointers, since precedence prevents + * anything being concatenated to any individual branch. The + * "next" pointer of the last BRANCH in a choice points to the + * thing following the whole choice. This is also where the + * final "next" pointer of each individual branch points; each + * branch starts with the operand node of a BRANCH node. + * + * BACK Normal "next" pointers all implicitly point forward; BACK + * exists to make loop structures possible. + * + * STAR,PLUS '?', and complex '*' and '+', are implemented as circular + * BRANCH structures using BACK. Simple cases (one character + * per match) are implemented with STAR and PLUS for speed + * and to minimize recursive plunges. + * + * OPEN,CLOSE ...are numbered at compile time. + */ + +/* The following have no fixed length. */ +#ifndef DOINIT +extern char varies[]; +#else +char varies[] = {BRANCH,BACK,STAR,PLUS, + REF+1,REF+2,REF+3,REF+4,REF+5,REF+6,REF+7,REF+8,REF+9,0}; +#endif + +/* The following always have a length of 1. */ +#ifndef DOINIT +extern char simple[]; +#else +char simple[] = {ANY,ANYOF,ANYBUT,ALNUM,NALNUM,SPACE,NSPACE,DIGIT,NDIGIT,0}; +#endif + +EXT char regdummy; + +/* + * A node is one char of opcode followed by two chars of "next" pointer. + * "Next" pointers are stored as two 8-bit pieces, high order first. The + * value is a positive offset from the opcode of the node containing it. + * An operand, if any, simply follows the node. (Note that much of the + * code generation knows about this implicit relationship.) + * + * Using two bytes for the "next" pointer is vast overkill for most things, + * but allows patterns to get big without disasters. + * + * [If REGALIGN is defined, the "next" pointer is always aligned on an even + * boundary, and reads the offset directly as a short. Also, there is no + * special test to reverse the sign of BACK pointers since the offset is + * stored negative.] + */ + +#ifndef gould +#ifndef cray +#define REGALIGN +#endif +#endif + +#define OP(p) (*(p)) + +#ifndef lint +#ifdef REGALIGN +#define NEXT(p) (*(short*)(p+1)) +#else +#define NEXT(p) (((*((p)+1)&0377)<<8) + (*((p)+2)&0377)) +#endif +#else /* lint */ +#define NEXT(p) 0 +#endif /* lint */ + +#define OPERAND(p) ((p) + 3) + +#ifdef REGALIGN +#define NEXTOPER(p) ((p) + 4) +#else +#define NEXTOPER(p) ((p) + 3) +#endif + +#define MAGIC 0234 + +/* + * Utility definitions. + */ +#ifndef lint +#ifndef CHARBITS +#define UCHARAT(p) ((int)*(unsigned char *)(p)) +#else +#define UCHARAT(p) ((int)*(p)&CHARBITS) +#endif +#else /* lint */ +#define UCHARAT(p) regdummy +#endif /* lint */ + +#define FAIL(m) fatal("/%s/: %s",regprecomp,m) + +char *regnext(); +#ifdef DEBUGGING +void regdump(); +char *regprop(); +#endif + |