basic version of catch

src/main.cpp

@@ -363,6 +363,12 @@ GroundValue literalToGroundValue(const Literal& lit) {
     return gv;
 }
 
+/*
+    catches stackmap
+    This stores all catches in a scope, to catch errors before they happen.
+*/
+stack<map<string, Direct>> catches;
+
 Literal groundValueToLiteral(const GroundValue& gv) {
     Literal lit;
     switch (gv.type) {
@@ -385,14 +391,30 @@ Literal groundValueToLiteral(const GroundValue& gv) {
     return lit;
 }
 
+// Forward declaration of setVal for error function
+void setVal(string varName, Literal value);
+
 /*
     error function
     Takes a string (which is a debug message) and prints it to the console, letting the
     user know what went wrong with the program.
 */
-void error(string in, string errCode = "syntaxError", int exitc = 1) {
+int error(string in, string errCode = "syntaxError", int exitc = 1) {
+    int pops = 0;
+    while (catches.size() > 0) {
+        if (catches.top().find(errCode) != catches.top().end()) {
+            Literal tmpLit;
+            tmpLit.val = false;
+            setVal(catches.top()[errCode].varName, tmpLit);
+            return pops;
+        } else {
+            catches.pop();
+            pops ++;
+        }
+    }
     cout << "\033[31m" + errCode + ": \033[39m" << in << endl;
     exit(exitc);
+    return pops;
 }
 
 /*
@@ -590,6 +612,10 @@ void preProcessLabels(vector<Instruction> instructions) {
     function for the program.
 */
 Literal exec(vector<Instruction> in, bool executingFunction) {
+    {
+        map<string, Direct> tmp;
+        catches.push(tmp);
+    }
     for (int i = 0; i < in.size(); i++) {
         Instruction l = in[i];
         if (processingFunction) {
@@ -930,11 +956,33 @@ Literal exec(vector<Instruction> in, bool executingFunction) {
                 if (l.args.size() < 2) {
                     error("Could not find all arguments for Catch inbuilt");
                 }
+
+                {
+                    string errCode;
+                    Direct varRef;
+
                     if (holds_alternative<Literal>(l.args[0])) {
                         if (holds_alternative<string>(get<Literal>(l.args[0]).val)) {
+                            errCode = get<string>(get<Literal>(l.args[0]).val);
+                        } else {
+                            error("First argument of catch must be a string literal");
+                        }
+                    } else {
+                        error("First argument of catch must be a string literal");
+                    }
 
+                    if (holds_alternative<Direct>(l.args[1])) {
+                        varRef = get<Direct>(l.args[1]);
+                    } else {
+                        error("Second argument of catch must be a direct reference");
                     }
+
+                    catches.top()[errCode] = varRef;
+                    Literal tmpLit;
+                    tmpLit.val = true;
+                    setVal(varRef.varName, tmpLit);
                 }
+                break;
             /*
                 set instruction
                 This instruction sets a variable to a provided value.