Author: pmichaud
Date: Tue Dec 9 16:01:45 2008
New Revision: 33736
Modified:
trunk/languages/perl6/src/classes/List.pir
Log:
[rakudo]: Refactor infix:<X> to avoid numeric list indices.
Modified: trunk/languages/perl6/src/classes/List.pir
==============================================================================
--- trunk/languages/perl6/src/classes/List.pir (original)
+++ trunk/languages/perl6/src/classes/List.pir Tue Dec 9 16:01:45 2008
@@ -740,80 +740,60 @@
.sub 'infix:X'
.param pmc args :slurpy
.local pmc res
- res = new 'List'
- # Algorithm: we'll maintain a list of counters for each list, incrementing
- # the counter for the right-most list and, when it we reach its final
- # element, roll over the counter to the next list to the left as we go.
- .local pmc counters
- .local pmc list_elements
- .local int num_args
- counters = new 'FixedIntegerArray'
- list_elements = new 'FixedIntegerArray'
- num_args = elements args
- counters = num_args
- list_elements = num_args
+ .local pmc res, outer, inner, it, val
+ res = new 'List'
- # Get element count for each list.
- .local int i
- .local pmc cur_list
- i = 0
-elem_get_loop:
- if i >= num_args goto elem_get_loop_end
- cur_list = args[i]
- $I0 = elements cur_list
- list_elements[i] = $I0
- inc i
- goto elem_get_loop
-elem_get_loop_end:
+ ## if the are no arguments, result is empty list
+ unless args goto done
- # Now we'll start to produce them.
- .local int res_count
- res_count = 0
-produce_next:
-
- # Start out by building list at current counters.
- .local pmc new_list
- new_list = new 'Perl6Array'
- i = 0
-cur_perm_loop:
- if i >= num_args goto cur_perm_loop_end
- $I0 = counters[i]
- $P0 = args[i]
- $P1 = $P0[$I0]
- new_list[i] = $P1
- inc i
- goto cur_perm_loop
-cur_perm_loop_end:
- new_list = new 'ObjectRef', new_list
- res[res_count] = new_list
- inc res_count
-
- # Now increment counters.
- i = num_args - 1
-inc_counter_loop:
- $I0 = counters[i]
- $I1 = list_elements[i]
- inc $I0
- counters[i] = $I0
-
- # In simple case, we just increment this and we're done.
- if $I0 < $I1 goto inc_counter_loop_end
-
- # Otherwise we have to carry.
- counters[i] = 0
-
- # If we're on the first element, all done.
- if i == 0 goto all_done
-
- # Otherwise, loop.
- dec i
- goto inc_counter_loop
-inc_counter_loop_end:
- goto produce_next
+ ## get the first arg in list context
+ outer = shift args
+ outer = 'list'(outer)
+
+ ## if this argument is empty, result is empty list
+ unless outer goto done
+
+ ## if no more args, then build result from only arg
+ unless args goto one_arg
+
+ ## There are more args, so recursively compute their cross.
+ ## If that list is empty, our cross is empty.
+ inner = 'infix:X'(args :flat)
+ unless inner goto done
+
+ ## otherwise, loop through all elements of our first arg
+ it = iter outer
+ outer_loop:
+ unless it goto done
+ val = shift it
+ ## add the value to a clone of each inner result list
+ $P1 = iter inner
+ inner_loop:
+ unless $P1 goto outer_loop
+ ## get a result list, clone it
+ $P0 = shift $P1
+ $P0 = clone $P0
+ ## add our outer value to the beginning
+ unshift $P0, val
+ ## save it in the result list
+ push res, $P0
+ goto inner_loop
+
+ ## if call to infix:X had only one argument, our result
+ ## is a list of 1-element lists.
+ one_arg:
+ it = iter outer
+ one_arg_loop:
+ unless it goto done
+ val = shift it
+ $P0 = new 'List'
+ push $P0, val
+ push res, $P0
+ goto one_arg_loop
-all_done:
- .return(res)
+ done:
+ .return (res)
.end
