+/****************************************************************************
+PARAMETERS:
+str - text of #if statement
+
+RETURNS:
+true or false depending on how it evaluated
+
+REMARKS:
+
+SEE ALSO:
+wxIfElseVariable
+****************************************************************************/
+bool ParseIfStatementValue(wxString &str) {
+
+ // Find out if the tag has parenthesis
+ // recursive to parse the text within the parenthesis,
+ // replacing the text with 1 or 0, (hardcoded true or false)
+ int b;
+ while ((b = str.Find('(')) != -1) {
+ int e;
+ // Find the matching parenthesis
+ int nextbeg, nextend;
+ int parencount = 1, min = b+1;
+ do {
+
+ nextbeg = str.find('(', min);
+ nextend = str.find(')', min);
+ if (nextbeg < nextend && nextbeg != wxString::npos) {
+ parencount++;
+ min = nextbeg+1;
+ }
+ else {
+ parencount--;
+ min = nextend+1;
+ }
+
+ if (nextend == wxString::npos) {
+ #ifdef CHECKED
+ wxMessageBox("wxHTML #if\\else error: Unmatched parenthesis in #if expression.","Error",wxICON_ERROR);
+ #endif
+ return true;
+ }
+ // once parencount reaches 0 again we have found our matchin )
+ } while (parencount > 0);
+
+ e = nextend;
+
+ // Extract the expression from the parenthesis block and recurse
+ // to solve it.
+ wxString tag;
+ tag = str.Mid(b+1, e-b-1);
+ bool val = ParseIfStatementValue(tag);
+ // Add extra spaces just in case of NOT(VAL)
+ if (val) str = str.Mid(0, b) + " 1" + str.Mid(e+1);
+ else str = str.Mid(0, b) + " 0" + str.Mid(e+1);
+
+ }
+
+ // Remove spaces from left and right
+ str.Trim(false);
+ str.Trim(true);
+
+ // Convert text method of operators "AND" and "OR" to c style
+ // this makes only one special case necessary for each later on
+ str.Replace(" AND ", "&&");
+ str.Replace(" OR ", "||");
+
+ // We use ReverseFind so that the whole left expression gets evaluated agains
+ // the right single item, creating a left -> right evaluation
+ // Search for || operators, recurse to solve (so we don't have to handle special cases here)
+ int and, or;
+ and = ReverseFind(str, "&&");
+ or = ReverseFind(str, "||");
+ if ( (and != -1) || (or != -1) ) {
+ wxString tag1, tag2;
+ // handle the rightmost first to force left->right evaluation
+ if (and > or) {
+ return (
+ ParseIfStatementValue(tag2 = str.Mid(and+2)) &&
+ ParseIfStatementValue(tag1 = str.Mid(0, and)) );
+ }
+ else {
+ return (
+ ParseIfStatementValue(tag2 = str.Mid(or+2)) ||
+ ParseIfStatementValue(tag1 = str.Mid(0, or)) );
+ }
+
+ }
+
+ // By the time we get to this place in the function we are guarenteed to have a single
+ // variable operation, perhaps with a NOT or ! operator
+ bool notval = false;
+
+ // search for a NOT or ! operator
+ if (str.Mid(0, 1) == "!") {
+ str.Remove(0, 1);
+ str.Trim(false); // trim spaces from left
+ notval = true;
+ }
+ else if (str.Mid(0,4).CmpNoCase("NOT ") == 0) {
+ str.Remove(0, 4);
+ str.Trim(false); // trim any extra spaces from left
+ notval = true;
+ }
+
+ // now all we have left is the name of the class or a hardcoded 0 or 1
+
+ if (str == "") {
+ #ifdef CHECKED
+ wxMessageBox("wxHTML #if\\else error: Empty expression in #if\\#elif statement.","Error",wxICON_ERROR);
+ #endif
+ return true;
+ }
+
+ // check for hardcoded 0 and 1 cases, (these are used by parenthesis catcher)
+ // this just decomplicates the recursion algorithm
+ if (str == "0") return notval;
+ if (str == "1") return !notval;
+
+ // Grab the value from the variable class identified by cname
+ bool value = wxIfElseVariable::FindValue(str);
+ if (notval) value = !value;
+ return value;
+
+}
projects / wxWidgets.git / blobdiff