[svn:parrot] r41561 - in branches/pct-rx/compilers/pct/src: PAST Regex

[pmichaud at svn.parrot.org]

Author: pmichaud
Date: Tue Sep 29 20:58:49 2009
New Revision: 41561
URL: https://trac.parrot.org/parrot/changeset/41561

Log:
[pct-rx]:  Add some Cursor methods.

Modified:
   branches/pct-rx/compilers/pct/src/PAST/Compiler-Regex.pir
   branches/pct-rx/compilers/pct/src/Regex/Cursor.pir

Modified: branches/pct-rx/compilers/pct/src/PAST/Compiler-Regex.pir
==============================================================================
--- branches/pct-rx/compilers/pct/src/PAST/Compiler-Regex.pir	Tue Sep 29 15:40:40 2009	(r41560)
+++ branches/pct-rx/compilers/pct/src/PAST/Compiler-Regex.pir	Tue Sep 29 20:58:49 2009	(r41561)
@@ -61,7 +61,8 @@
     $P0 = self.'post_regex'(node)
     ops.'push'($P0)
     ops.'push'(faillabel)
-    self.'!cursorop'(ops, '!mark_cut', 3, rep, pos, '$I10')
+    self.'!cursorop'(ops, '!mark_fail', 3, rep, pos, '$I10')
+    ops.'push_pirop'('lt', pos, 0, faillabel)
     ops.'push_pirop'('jump', '$I10')
     .return (ops)
 .end
@@ -417,7 +418,7 @@
     peekcut = '!mark_peek'
     if backtrack != 'r' goto greedy_1
     needmark = 1
-    peekcut = '!mark_cut'
+    peekcut = '!mark_commit'
   greedy_1:
     if min == 0 goto greedy_2
     unless needmark goto greedy_loop

Modified: branches/pct-rx/compilers/pct/src/Regex/Cursor.pir
==============================================================================
--- branches/pct-rx/compilers/pct/src/Regex/Cursor.pir	Tue Sep 29 15:40:40 2009	(r41560)
+++ branches/pct-rx/compilers/pct/src/Regex/Cursor.pir	Tue Sep 29 20:58:49 2009	(r41561)
@@ -23,10 +23,106 @@
     .return ()
 .end
 
-=head2 Methods
+=head2 Private methods
 
 =over 4
 
+=item !mark_push(rep, pos, mark)
+
+Push a new backtracking point onto the cursor with the given
+C<rep>, C<pos>, and backtracking C<mark>.  (The C<mark> is typically
+the address of a label to branch to when backtracking occurs.)
+
+=cut
+
+.sub '!mark_push' :method
+    .param int rep
+    .param int pos
+    .param int mark
+
+    .local pmc bstack, mstack
+    bstack = getattribute self, '@!bstack'
+    mstack = getattribute self, '@!mstack'
+
+    push bstack, mark
+    push bstack, pos
+    push bstack, rep
+    $I0 = mstack
+    push bstack, $I0
+.end
+
+=item !mark_fail([mark])
+
+Remove the most recent C<mark> and backtrack the cursor to the
+point given by that mark.  If no C<mark> is provided, then
+backtracks the most recent mark.  Returns the backtracked
+values of repetition count, cursor position, and mark (address).
+
+=cut
+
+.sub '!mark_fail' :method
+    .param int mark            :optional
+    .param int has_mark        :opt_flag
+
+    .local pmc bstack, mstack
+    bstack = getattribute self, '@!bstack'
+    bstack = getattribute self, '@!mstack'
+
+    # get the frame associated with the mark
+    .local int bptr, rep, pos, mark, mptr
+    bptr = self.'!mark_bptr'(mark, has_mark)
+
+    # retrieve the mark, pos, rep, and match index from the frame
+    mark = bstack[bptr]
+    $I0  = bptr + 1
+    pos  = bstack[$I0]
+    inc $I0
+    rep  = bstack[$I0]
+    inc $I0
+    mptr = bstack[$I0]
+
+    # release the backtracked stack elements
+    assign bstack, bptr
+    assign mstack, mptr
+
+    .local pmc match
+    match = mstack[-1]
+
+    # return mark values
+    .return (rep, pos, mark, match)
+.end
+
+
+=item '!mark_commit'(mark)
+
+Like C<!mark_fail> above this backtracks the cursor to C<mark>
+(releasing any intermediate marks), but preserves the current 
+match state.
+
+=cut
+
+.sub '!mark_commit' :method
+    .param int mark
+
+    # preserve the current match object
+    .local pmc mstack, match
+    mstack = getattribute self, '@!mstack'
+
+    # backtrack
+    .local int rep, pos, mark
+    (rep, pos, mark, $P0) = self.'!mark_fail'(mark)
+
+    # if match we backtracked to is the same as this one,
+    # we don't need to preserve it specially
+    $I0 = issame $P0, match
+    if $I0 goto done
+    # save current match state
+    push mstack, match
+
+  done:
+    .return (rep, pos, mark, match)
+.end
+
 =back
 
 =head1 AUTHORS