From b4a537f95c7f786276ddd4e9976497f819e218bd Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Henrik=20Grubbstr=C3=B6m=20=28Grubba=29?=
<grubba@grubba.org>
Date: Mon, 8 Nov 1999 22:19:05 +0100
Subject: [PATCH] Added some documentation. Disabled some debug.
Rev: bin/mktreeopt.pike:1.8
---
bin/mktreeopt.pike | 81 +++++++++++++++++++++++++++++++++++++++++++---
1 file changed, 77 insertions(+), 4 deletions(-)
diff --git a/bin/mktreeopt.pike b/bin/mktreeopt.pike
index a8404830b3..230af98aa5 100644
--- a/bin/mktreeopt.pike
+++ b/bin/mktreeopt.pike
@@ -1,11 +1,75 @@
/*
- * $Id: mktreeopt.pike,v 1.7 1999/11/08 17:07:41 grubba Exp $
+ * $Id: mktreeopt.pike,v 1.8 1999/11/08 21:19:05 grubba Exp $
*
* Generates tree-transformation code from a specification.
*
* Henrik Grubbstr�m 1999-11-06
*/
+/*
+ * Notes about the generated code:
+ *
+ * The node to be examined can have 4 basic configurations:
+ *
+ * X X X X
+ * / \ / \ / \ / \
+ * - - - X X - X X
+ *
+ * The node is then matched against the 9 kinds of match nodes:
+ *
+ * X X X
+ * / \ / \ / \
+ * - - - X - *
+ *
+ * X X X
+ * / \ / \ / \
+ * X - X X X *
+ *
+ * X X X
+ * / \ / \ / \
+ * * - * X * *
+ *
+ * The match-order is determined by the manhattan distance from the node
+ *
+ * X
+ * / \
+ * - -
+ *
+ * in the table above.
+ *
+ *
+ * Pseudocode: (Real code needs fixing...)
+ *
+ * if (!car(n)) {
+ * if (!cdr(n)) {
+ * // Code for NULL-NULL
+ * } else {
+ * // Code for NULL-X
+ * }
+ * // Code for NULL-ANY
+ * if (!cdr(n)) {
+ * goto ANY_NULL;
+ * }
+ * goto ANY_X;
+ * } else if (!cdr(n)) {
+ * // Code for X-NULL
+ * ANY_NULL:
+ * // Code for ANY-NULL
+ * if (car(n)) {
+ * goto X_ANY;
+ * }
+ * } else {
+ * // Code for X-X
+ * X_ANY:
+ * // Code for X-ANY
+ * if (cdr(n)) {
+ * ANY_X:
+ * // Code for ANY-X
+ * }
+ * }
+ * // Code for ANY-ANY
+ */
+
mapping(string: mixed) rules = ([]);
void fail(string msg, mixed ... args)
@@ -418,7 +482,7 @@ void parse_data()
object(node) n = read_node();
- werror(sprintf("%s:\n", n));
+ // werror(sprintf("%s:\n", n));
if (rules[n->token]) {
rules[n->token] += ({ n });
@@ -692,10 +756,14 @@ string generate_car_match(array(object(node)) rule_set, string indent)
if (label) {
res += indent + label + ":\n";
- }
- if (sizeof(car_any_cdr_null)) {
res += generate_car_match(car_any_cdr_null, indent + " ");
+
+ // We need to skip past the any-section.
+
+ label = sprintf("label_%d", label_cnt++);
+
+ res += indent + " goto " + label + ";\n";
}
res += indent + "}";
@@ -733,6 +801,11 @@ string generate_car_match(array(object(node)) rule_set, string indent)
res += generate_cdr_match(cdr_follow, indent);
}
+ if (label) {
+ res += indent[2..] + label + ":\n" +
+ indent + ";\t/* Keep compiler happy */\n";
+ }
+
return res;
}
--
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