[gcalctool/gcalctool-new-parser] Get percentages working again

[Robert Ancell <rancell src gnome org>]

commit e0f094bb1de52ca2a6d1fbf2e5c4ffe97445a289
Author: Robert Ancell <robert ancell canonical com>
Date:   Sun Oct 16 16:55:27 2011 +1100

    Get percentages working again

 src/mp-equation.c |   41 +++++++++++++++++++++++++++++++++++------
 1 files changed, 35 insertions(+), 6 deletions(-)
---
diff --git a/src/mp-equation.c b/src/mp-equation.c
index 46fd8c1..fa0e7da 100644
--- a/src/mp-equation.c
+++ b/src/mp-equation.c
@@ -264,6 +264,7 @@ typedef enum
 {
     TOKEN_NONE,
     TOKEN_NUMBER,
+    TOKEN_PERCENTAGE,
     TOKEN_SUPER_NUMBER,
     TOKEN_SUB_NUMBER,
     TOKEN_ADD,
@@ -275,7 +276,6 @@ typedef enum
     TOKEN_ROOT,
     TOKEN_CUBE_ROOT,
     TOKEN_FOURTH_ROOT,
-    TOKEN_PERCENTAGE,
     TOKEN_FACTORIAL,
     TOKEN_BOOLEAN_AND,
     TOKEN_BOOLEAN_OR,
@@ -408,8 +408,6 @@ parse(MPEquationOptions *options, const gchar *expression, GList **tokens)
                 current_token = TOKEN_CUBE_ROOT;
             else if (c == 0x221C /* â */)
                 current_token = TOKEN_FOURTH_ROOT;
-            else if (c == '%')
-                current_token = TOKEN_PERCENTAGE;
             else if (c == '!')
                 current_token = TOKEN_FACTORIAL;
             else if (c == 0x2227 /* â */)
@@ -468,6 +466,24 @@ parse(MPEquationOptions *options, const gchar *expression, GList **tokens)
             }
             else if (g_unichar_isxdigit(c) || unichar_issubdigit(c) || unichar_isfraction(c)) {
             }
+            else if (c == '%') {
+                Token *t;
+                gchar *string;
+
+                current_token = TOKEN_NONE;
+                t = token_new(TOKEN_PERCENTAGE, token_start, i + 1);
+                string = token_get_string(t);
+                string[strlen (string) - 1] = '\0';
+                if (!mp_set_from_string(string, options->base, &t->value))
+                {
+                    mp_divide_integer (&t->value, 100, &t->value);
+                    *tokens = g_list_append(*tokens, t);
+                }
+                else
+                    return PARSER_ERR_INVALID;
+
+                g_free(string);
+            }
             else {
                 Token *t;
                 gchar *string;
@@ -670,7 +686,7 @@ replace_block(GList **first, GList **last, GList *start, GList *end, MPNumber *r
 static MPErrorCode
 has_value (Token *token)
 {
-    return token->type == TOKEN_EXPRESSION || token->type == TOKEN_NUMBER || token->type == TOKEN_VARIABLE;
+    return token->type == TOKEN_EXPRESSION || token->type == TOKEN_NUMBER || token->type == TOKEN_PERCENTAGE || token->type == TOKEN_VARIABLE;
 }
 
 
@@ -795,10 +811,23 @@ do_operation (MPEquationOptions *options, GList **first, GList **last, GList *op
 
     switch (o->type) {
     case TOKEN_ADD:
-        mp_add(&a->value, &b->value, &result);
+        if (b->type == TOKEN_PERCENTAGE)
+        {
+            mp_multiply(&a->value, &b->value, &result);
+            mp_add(&result, &a->value, &result);
+        }
+        else
+            mp_add(&a->value, &b->value, &result);
         break;
     case TOKEN_SUBTRACT:
-        mp_subtract(&a->value, &b->value, &result);
+        if (b->type == TOKEN_PERCENTAGE)
+        {
+            mp_multiply(&a->value, &b->value, &result);
+            mp_invert_sign(&result, &result);
+            mp_add(&result, &a->value, &result);
+        }
+        else
+            mp_subtract(&a->value, &b->value, &result);
         break;
     case TOKEN_MULTIPLY:
         mp_multiply(&a->value, &b->value, &result);