* "It all comes from here, the stench and the peril." --Frodo
*/
+/* toke.c
+ *
+ * This file is the tokenizer for Perl. It's closely linked to the
+ * parser, perly.y.
+ *
+ * The main routine is yylex(), which returns the next token.
+ */
+
#include "EXTERN.h"
#define PERL_IN_TOKE_C
#include "perl.h"
* 1999-02-27 mjd-perl-patch@plover.com */
#define isCONTROLVAR(x) (isUPPER(x) || strchr("[\\]^_?", (x)))
-/* The following are arranged oddly so that the guard on the switch statement
+/* LEX_* are values for PL_lex_state, the state of the lexer.
+ * They are arranged oddly so that the guard on the switch statement
* can get by with a single comparison (if the compiler is smart enough).
*/
#include "keywords.h"
+/* CLINE is a macro that ensures PL_copline has a sane value */
+
#ifdef CLINE
#undef CLINE
#endif
#define CLINE (PL_copline = (PL_curcop->cop_line < PL_copline ? PL_curcop->cop_line : PL_copline))
+/*
+ * Convenience functions to return different tokens and prime the
+ * tokenizer for the next token. They all take an argument.
+ *
+ * TOKEN : generic token (used for '(', DOLSHARP, etc)
+ * OPERATOR : generic operator
+ * AOPERATOR : assignment operator
+ * PREBLOCK : beginning the block after an if, while, foreach, ...
+ * PRETERMBLOCK : beginning a non-code-defining {} block (eg, hash ref)
+ * PREREF : *EXPR where EXPR is not a simple identifier
+ * TERM : expression term
+ * LOOPX : loop exiting command (goto, last, dump, etc)
+ * FTST : file test operator
+ * FUN0 : zero-argument function
+ * FUN1 : not used
+ * BOop : bitwise or or xor
+ * BAop : bitwise and
+ * SHop : shift operator
+ * PWop : power operator
+ * PMop : matching operator
+ * Aop : addition-level operator
+ * Mop : multiplication-level operator
+ * Eop : equality-testing operator
+ * Rop : relational operator <= != gt
+ *
+ * Also see LOP and lop() below.
+ */
+
#define TOKEN(retval) return (PL_bufptr = s,(int)retval)
#define OPERATOR(retval) return (PL_expect = XTERM,PL_bufptr = s,(int)retval)
#define AOPERATOR(retval) return ao((PL_expect = XTERM,PL_bufptr = s,(int)retval))
/* grandfather return to old style */
#define OLDLOP(f) return(yylval.ival=f,PL_expect = XTERM,PL_bufptr = s,(int)LSTOP)
+/*
+ * S_ao
+ *
+ * This subroutine detects &&= and ||= and turns an ANDAND or OROR
+ * into an OP_ANDASSIGN or OP_ORASSIGN
+ */
+
STATIC int
S_ao(pTHX_ int toketype)
{
return toketype;
}
+/*
+ * S_no_op
+ * When Perl expects an operator and finds something else, no_op
+ * prints the warning. It always prints "<something> found where
+ * operator expected. It prints "Missing semicolon on previous line?"
+ * if the surprise occurs at the start of the line. "do you need to
+ * predeclare ..." is printed out for code like "sub bar; foo bar $x"
+ * where the compiler doesn't know if foo is a method call or a function.
+ * It prints "Missing operator before end of line" if there's nothing
+ * after the missing operator, or "... before <...>" if there is something
+ * after the missing operator.
+ */
+
STATIC void
S_no_op(pTHX_ char *what, char *s)
{
PL_bufptr = oldbp;
}
+/*
+ * S_missingterm
+ * Complain about missing quote/regexp/heredoc terminator.
+ * If it's called with (char *)NULL then it cauterizes the line buffer.
+ * If we're in a delimited string and the delimiter is a control
+ * character, it's reformatted into a two-char sequence like ^C.
+ * This is fatal.
+ */
+
STATIC void
S_missingterm(pTHX_ char *s)
{
Perl_croak(aTHX_ "Can't find string terminator %c%s%c anywhere before EOF",q,s,q);
}
+/*
+ * Perl_deprecate
+ * Warns that something is deprecated. Duh.
+ */
+
void
Perl_deprecate(pTHX_ char *s)
{
Perl_warner(aTHX_ WARN_DEPRECATED, "Use of %s is deprecated", s);
}
+/*
+ * depcom
+ * Deprecate a comma-less variable list. Called from three places
+ * in the tokenizer.
+ */
+
STATIC void
S_depcom(pTHX)
{
deprecate("comma-less variable list");
}
+/*
+ * text filters for win32 carriage-returns, utf16-to-utf8 and
+ * utf16-to-utf8-reversed, whatever that is.
+ */
+
#ifdef WIN32
STATIC I32
return count;
}
+/*
+ * Perl_lex_start
+ * Initialize variables. Called by perl.c. It uses the Perl stack
+ * to save its state (for recursive calls to the parser).
+ */
+
void
Perl_lex_start(pTHX_ SV *line)
{
PL_rsfp = 0;
}
+/*
+ * Perl_lex_end
+ * Tidy up. Called from pp_ctl.c in the sv_compile_2op(), doeval(),
+ * and pp_leaveeval() subroutines.
+ */
+
void
Perl_lex_end(pTHX)
{
PL_doextract = FALSE;
}
+/*
+ * S_incline
+ * This subroutine has nothing to do with tilting, whether at windmills
+ * or pinball tables. Its name is short for "increment line". It
+ * increments the current line number in PL_curcop->cop_line and checks
+ * to see whether the line starts with a comment of the form
+ * # line 500
+ * If so, it sets the current line number to the number in the comment.
+ */
+
STATIC void
S_incline(pTHX_ char *s)
{
PL_curcop->cop_line = atoi(n)-1;
}
+/*
+ * S_skipspace
+ * Called to gobble the appropriate amount and type of whitespace.
+ * Skips comments as well.
+ */
+
STATIC char *
S_skipspace(pTHX_ register char *s)
{
if (*s++ == '\n' && PL_in_eval && !PL_rsfp)
incline(s);
}
+
+ /* comment */
if (s < PL_bufend && *s == '#') {
while (s < PL_bufend && *s != '\n')
s++;
}
}
}
+
+ /* only continue to recharge the buffer if we're at the end
+ * of the buffer, we're not reading from a source filter, and
+ * we're in normal lexing mode
+ */
if (s < PL_bufend || !PL_rsfp || PL_lex_state != LEX_NORMAL)
return s;
+
+ /* try to recharge the buffer */
if ((s = filter_gets(PL_linestr, PL_rsfp, (prevlen = SvCUR(PL_linestr)))) == Nullch) {
+ /* end of file. Add on the -p or -n magic */
if (PL_minus_n || PL_minus_p) {
sv_setpv(PL_linestr,PL_minus_p ?
";}continue{print or die qq(-p destination: $!\\n)" :
}
else
sv_setpv(PL_linestr,";");
+
+ /* reset variables for next time we lex */
PL_oldoldbufptr = PL_oldbufptr = PL_bufptr = s = PL_linestart = SvPVX(PL_linestr);
PL_bufend = SvPVX(PL_linestr) + SvCUR(PL_linestr);
+
+ /* Close the filehandle. Could be from -P preprocessor,
+ * STDIN, or a regular file. If we were reading code from
+ * STDIN (because the commandline held no -e or filename)
+ * then we don't close it, we reset it so the code can
+ * read from STDIN too.
+ */
+
if (PL_preprocess && !PL_in_eval)
(void)PerlProc_pclose(PL_rsfp);
else if ((PerlIO*)PL_rsfp == PerlIO_stdin())
PL_rsfp = Nullfp;
return s;
}
+
+ /* not at end of file, so we only read another line */
PL_linestart = PL_bufptr = s + prevlen;
PL_bufend = s + SvCUR(PL_linestr);
s = PL_bufptr;
incline(s);
+
+ /* debugger active and we're not compiling the debugger code,
+ * so store the line into the debugger's array of lines
+ */
if (PERLDB_LINE && PL_curstash != PL_debstash) {
SV *sv = NEWSV(85,0);
}
}
+/*
+ * S_check_uni
+ * Check the unary operators to ensure there's no ambiguity in how they're
+ * used. An ambiguous piece of code would be:
+ * rand + 5
+ * This doesn't mean rand() + 5. Because rand() is a unary operator,
+ * the +5 is its argument.
+ */
+
STATIC void
S_check_uni(pTHX)
{
}
}
+/* workaround to replace the UNI() macro with a function. Only the
+ * hints/uts.sh file mentions this. Other comments elsewhere in the
+ * source indicate Microport Unix might need it too.
+ */
+
#ifdef CRIPPLED_CC
#undef UNI
#endif /* CRIPPLED_CC */
+/*
+ * LOP : macro to build a list operator. Its behaviour has been replaced
+ * with a subroutine, S_lop() for which LOP is just another name.
+ */
+
#define LOP(f,x) return lop(f,x,s)
+/*
+ * S_lop
+ * Build a list operator (or something that might be one). The rules:
+ * - if we have a next token, then it's a list operator [why?]
+ * - if the next thing is an opening paren, then it's a function
+ * - else it's a list operator
+ */
+
STATIC I32
S_lop(pTHX_ I32 f, expectation x, char *s)
{
return LSTOP;
}
+/*
+ * S_force_next
+ * When the tokenizer realizes it knows the next token (for instance,
+ * it is reordering tokens for the parser) then it can call S_force_next
+ * to make the current token be the next one. It will also set
+ * PL_nextval, and possibly PL_expect to ensure the lexer handles the
+ * token correctly.
+ */
+
STATIC void
S_force_next(pTHX_ I32 type)
{
}
}
+/*
+ * S_force_word
+ * When the lexer knows the next thing is a word (for instance, it has
+ * just seen -> and it knows that the next char is a word char, then
+ * it calls S_force_word to stick the next word into the PL_next lookahead.
+ *
+ * Arguments:
+ * char *start : start of the buffer
+ * int token : PL_next will be this type of bare word (e.g., METHOD,WORD)
+ * int check_keyword : if true, Perl checks to make sure the word isn't
+ * a keyword (do this if the word is a label, e.g. goto FOO)
+ * int allow_pack : if true, : characters will also be allowed (require,
+ * use, etc. do this)
+ * int allow_initial_tick : used by the "sub" tokenizer only.
+ */
+
STATIC char *
S_force_word(pTHX_ register char *start, int token, int check_keyword, int allow_pack, int allow_initial_tick)
{
return s;
}
+/*
+ * S_force_ident
+ * Called when the tokenizer wants $foo *foo &foo etc, but the program
+ * text only contains the "foo" portion. The first argument is a pointer
+ * to the "foo", and the second argument is the type symbol to prefix.
+ * Forces the next token to be a "WORD".
+ * Creates the symbol if it didn't already exist (through the gv_fetchpv
+ * call).
+ */
+
STATIC void
S_force_ident(pTHX_ register char *s, int kind)
{
}
}
+/*
+ * S_force_version
+ * Forces the next token to be a version number.
+ */
+
STATIC char *
S_force_version(pTHX_ char *s)
{
return (s);
}
+/*
+ * S_tokeq
+ * Tokenize a quoted string passed in as an SV. It finds the next
+ * chunk, up to end of string or a backslash. It may make a new
+ * SV containing that chunk (if HINT_NEW_STRING is on). It also
+ * turns \\ into \.
+ */
+
STATIC SV *
S_tokeq(pTHX_ SV *sv)
{
return sv;
}
+/*
+ * Now come three functions related to double-quote context,
+ * S_sublex_start, S_sublex_push, and S_sublex_done. They're used when
+ * converting things like "\u\Lgnat" into ucfirst(lc("gnat")). They
+ * interact with PL_lex_state, and create fake ( ... ) argument lists
+ * to handle functions and concatenation.
+ * They assume that whoever calls them will be setting up a fake
+ * join call, because each subthing puts a ',' after it. This lets
+ * "lower \luPpEr"
+ * become
+ * join($, , 'lower ', lcfirst( 'uPpEr', ) ,)
+ *
+ * (I'm not sure whether the spurious commas at the end of lcfirst's
+ * arguments and join's arguments are created or not).
+ */
+
+/*
+ * S_sublex_start
+ * Assumes that yylval.ival is the op we're creating (e.g. OP_LCFIRST).
+ *
+ * Pattern matching will set PL_lex_op to the pattern-matching op to
+ * make (we return THING if yylval.ival is OP_NULL, PMFUNC otherwise).
+ *
+ * OP_CONST and OP_READLINE are easy--just make the new op and return.
+ *
+ * Everything else becomes a FUNC.
+ *
+ * Sets PL_lex_state to LEX_INTERPPUSH unless (ival was OP_NULL or we
+ * had an OP_CONST or OP_READLINE). This just sets us up for a
+ * call to S_sublex_push().
+ */
+
STATIC I32
S_sublex_start(pTHX)
{
return FUNC;
}
+/*
+ * S_sublex_push
+ * Create a new scope to save the lexing state. The scope will be
+ * ended in S_sublex_done. Returns a '(', starting the function arguments
+ * to the uc, lc, etc. found before.
+ * Sets PL_lex_state to LEX_INTERPCONCAT.
+ */
+
STATIC I32
S_sublex_push(pTHX)
{
return '(';
}
+/*
+ * S_sublex_done
+ * Restores lexer state after a S_sublex_push.
+ */
+
STATIC I32
S_sublex_done(pTHX)
{
return yylex();
}
- /* Is there a right-hand side to take care of? */
+ /* Is there a right-hand side to take care of? (s//RHS/ or tr//RHS/) */
if (PL_lex_repl && (PL_lex_inwhat == OP_SUBST || PL_lex_inwhat == OP_TRANS)) {
PL_linestr = PL_lex_repl;
PL_lex_inpat = 0;
return s;
}
-/* This is the one truly awful dwimmer necessary to conflate C and sed. */
+/* S_intuit_more
+ * Returns TRUE if there's more to the expression (e.g., a subscript),
+ * FALSE otherwise.
+ * This is the one truly awful dwimmer necessary to conflate C and sed.
+ *
+ * It deals with "$foo[3]" and /$foo[3]/ and /$foo[0123456789$]+/
+ *
+ * ->[ and ->{ return TRUE
+ * { and [ outside a pattern are always subscripts, so return TRUE
+ * if we're outside a pattern and it's not { or [, then return FALSE
+ * if we're in a pattern and the first char is a {
+ * {4,5} (any digits around the comma) returns FALSE
+ * if we're in a pattern and the first char is a [
+ * [] returns FALSE
+ * [SOMETHING] has a funky algorithm to decide whether it's a
+ * character class or not. It has to deal with things like
+ * /$foo[-3]/ and /$foo[$bar]/ as well as /$foo[$\d]+/
+ * anything else returns TRUE
+ */
+
STATIC int
S_intuit_more(pTHX_ register char *s)
{
if (*s == ']' || *s == '^')
return FALSE;
else {
+ /* this is terrifying, and it works */
int weight = 2; /* let's weigh the evidence */
char seen[256];
unsigned char un_char = 255, last_un_char;
return TRUE;
}
+/*
+ * S_intuit_method
+ *
+ * Does all the checking to disambiguate
+ * foo bar
+ * between foo(bar) and bar->foo. Returns 0 if not a method, otherwise
+ * FUNCMETH (bar->foo(args)) or METHOD (bar->foo args).
+ *
+ * First argument is the stuff after the first token, e.g. "bar".
+ *
+ * Not a method if bar is a filehandle.
+ * Not a method if foo is a subroutine prototyped to take a filehandle.
+ * Not a method if it's really "Foo $bar"
+ * Method if it's "foo $bar"
+ * Not a method if it's really "print foo $bar"
+ * Method if it's really "foo package::" (interpreted as package->foo)
+ * Not a method if bar is known to be a subroutne ("sub bar; foo bar")
+ * Not a method if bar is a filehandle or package, but is quotd with
+ * =>
+ */
+
STATIC int
S_intuit_method(pTHX_ char *start, GV *gv)
{
gv = 0;
}
s = scan_word(s, tmpbuf, sizeof tmpbuf, TRUE, &len);
+ /* start is the beginning of the possible filehandle/object,
+ * and s is the end of it
+ * tmpbuf is a copy of it
+ */
+
if (*start == '$') {
if (gv || PL_last_lop_op == OP_PRINT || isUPPER(*PL_tokenbuf))
return 0;
return 0;
}
+/*
+ * S_incl_perldb
+ * Return a string of Perl code to load the debugger. If PERL5DB
+ * is set, it will return the contents of that, otherwise a
+ * compile-time require of perl5db.pl.
+ */
+
STATIC char*
S_incl_perldb(pTHX)
{
#include "XSUB.h"
#endif
+/*
+ * restore_rsfp
+ * Restore a source filter.
+ */
+
static void
restore_rsfp(pTHXo_ void *f)
{
PL_rsfp = fp;
}
+/*
+ * restore_expect
+ * Restores the state of PL_expect when the lexing that begun with a
+ * start_lex() call has ended.
+ */
+
static void
restore_expect(pTHXo_ void *e)
{
PL_expect = (expectation)((char *)e - PL_tokenbuf);
}
+/*
+ * restore_lex_expect
+ * Restores the state of PL_lex_expect when the lexing that begun with a
+ * start_lex() call has ended.
+ */
+
static void
restore_lex_expect(pTHXo_ void *e)
{
/* a safe way to store a small integer in a pointer */
PL_lex_expect = (expectation)((char *)e - PL_tokenbuf);
}
-
projects / p5sagit/p5-mst-13.2.git / commitdiff