diff options
| -rw-r--r-- | ChangeLog | 8 | ||||
| -rw-r--r-- | match.c | 19 | ||||
| -rw-r--r-- | txr.1 | 27 |
3 files changed, 50 insertions, 4 deletions
@@ -1,3 +1,11 @@ +2013-05-15 Kaz Kylheku <kaz@kylheku.com> + + * match.c (match_fun): Support debug stop on the function + prior to the call. The first data line number is 1, not zero, + if there is data. + + * txr.1: Added usage example for match-fun. + 2013-05-14 Kaz Kylheku <kaz@kylheku.com> * txr.1: Documented time and url encoding/decoding functions. @@ -3698,14 +3698,23 @@ val match_filter(val name, val arg, val other_args) val match_fun(val name, val args, val input, val files) { - val spec = cons(cons(cons(name, args), nil), nil); + val call = cons(name, args); + val spec = cons(cons(call, nil), nil); val in_bindings = cdr(uw_get_match_context()); val data = if3(streamp(input), lazy_stream_cons(input), input); /* TODO: pass through source location context */ - match_files_ctx c = mf_all(spec, files, in_bindings, data, num(0)); - val ret = v_fun(&c); + match_files_ctx c = mf_all(spec, files, in_bindings, data, + if3(data, one, zero)); + val ret; + + debug_enter; + + debug_check(call, c.bindings, if2(consp(c.data), car(c.data)), + c.data_lineno, nil, nil); + + ret = v_fun(&c); if (ret == nil) return nil; @@ -3713,7 +3722,9 @@ val match_fun(val name, val args, val input, val files) if (ret == decline_k) sem_error(nil, lit("match_fun: function ~s not found"), name, nao); - return cons(c.bindings, cons(c.data, c.data_lineno)); + debug_return (cons(c.bindings, if3(c.data, cons(c.data, c.data_lineno), t))); + + debug_leave; } int extract(val spec, val files, val predefined_bindings) @@ -10358,6 +10358,33 @@ is one of two values. If the entire input was processed, the cdr field holds the symbol t. Otherwise it holds another cons cell whose car is the remainder of the list of lines which were not matched, and the cdr is the line number. +.TP +Example: + + @(define foo (x y)) + @x:@y + @line + @(end) + @(do + (format t "~s\n" + (match-fun 'foo '(a b) '("alpha:beta" "gamma" "omega") nil))) + + Output: + (((a . "alpha") (b . "beta")) ("omega") . 3) + +In the above example, the pattern function foo is called with arguments (a b). +These are unbound variables, so they correspond to parameters x and y +of the function. If x and y get bound, those values propagate to a and b. +The data being matched consists of the lines "alpha:beta", "gamma" and +"omega". Inside foo, x and y bind to "alpha" and "beta", and then the +line variable binds t "gamma". The input stream is left with "omega". + +Hence, the return value consists of the bindings of x and y transferred to a +and b, and the second cons cell giving information about the rest of the +stream: it is the part starting at "omega", which is line 3. Note that the +binding for for line variable does not propagate out of the pattern function +foo; it is local inside it. + .SH DEBUGGING FUNCTIONS .SS Functions source-loc and source-loc-str |