Start work on functions

docs/syntax.md

@@ -232,7 +232,21 @@ Some symbols specific to this category:
 
 Defines a function. All code between `fun` and `endfun` will be included in the function.
 
-Usage: `fun !functionname -type &var -type &var -type &var   # and so on...`
+Usage: `fun -type !functionname -type &var -type &var -type &var   # and so on...`
+
+Usage note: The first type specified before the function name must be the return type. The type displayed before all vars 
+
+#### local
+
+Defines a variable. The variable will be destroyed when the function is finished.
+
+Usage: `local &var $value`
+
+#### return
+
+Returns back to the main program (or other function that called this function). Also returns a value, which must be of the type defined when defining the function.
+
+Usage: `return $value`
 
 #### endfun
 

src/main.cpp

@@ -57,7 +57,8 @@ enum class Instructions {
     Setlist, Getlistat, Setlistat, Getlistsize, Listappend, Listprepend,
     Getstrcharat, Getstrsize,
     Stoi, Stod, Tostring,
-    Fun, Endfun, Pusharg, Call
+    Fun, Return, Endfun, Pusharg, Call,
+    Use, Extern
 };
 
 /*
@@ -122,6 +123,30 @@ struct List {
     vector<Literal> val;
 };
 
+/*
+    Direct struct
+    If the program being executed makes a direct reference, it is stored in a Direct
+    struct. For example, if the following line was written:
+        stdin &myVar
+    The Direct struct in the instruction should look like this:
+    {
+        varName = "myVar";
+    }
+*/
+struct Direct {
+    string varName;
+};
+
+/*
+    Function struct
+    Contains information needed to run a Ground function.
+*/
+struct Function {
+    int startPos;
+    Types returnType;
+    vector<pair<Direct, Types>> args;
+};
+
 /*
     ListRef struct
     Contains the name of a list referenced by the program. For example, if the
@@ -169,20 +194,6 @@ struct ValueRef {
     string varName;
 };
 
-/*
-    Direct struct
-    If the program being executed makes a direct reference, it is stored in a Direct
-    struct. For example, if the following line was written:
-        stdin &myVar
-    The Direct struct in the instruction should look like this:
-    {
-        varName = "myVar";
-    }
-*/
-struct Direct {
-    string varName;
-};
-
 /*
     Line struct
     If the program being executed makes a line reference, it is stored in a Line
@@ -1346,6 +1357,10 @@ void exec(vector<Instruction> in) {
                     }
                 }
                 break;
+            /*
+                end instructoin
+                Ends execution of the code, eith the status code provided.
+            */
             case Instructions::End:
                 if (l.args.size() < 1) {
                     error("Could not find all arguments required for End inbuilt");
@@ -1360,6 +1375,20 @@ void exec(vector<Instruction> in) {
                     error("First argument of end must be an int value");
                 }
                 break;
+            case Instructions::Fun:
+                break;
+            case Instructions::Return:
+                break;
+            case Instructions::Endfun:
+                break;
+            case Instructions::Pusharg:
+                break;
+            case Instructions::Call:
+                break;
+            case Instructions::Use:
+                break;
+            case Instructions::Extern:
+                break;
             default:
                 cout << "Still to be implemented" << endl;
                 break;
@@ -1486,6 +1515,13 @@ vector<Instruction> parser(vector<vector<string>> in) {
                 else if (i == "stoi") newInst.inst = Instructions::Stoi;
                 else if (i == "stod") newInst.inst = Instructions::Stod;
                 else if (i == "tostring") newInst.inst = Instructions::Tostring;
+                else if (i == "fun") newInst.inst = Instructions::Fun;
+                else if (i == "return") newInst.inst = Instructions::Return;
+                else if (i == "endfun") newInst.inst = Instructions::Endfun;
+                else if (i == "pusharg") newInst.inst = Instructions::Pusharg;
+                else if (i == "call") newInst.inst = Instructions::Call;
+                else if (i == "use") newInst.inst = Instructions::Use;
+                else if (i == "extern") newInst.inst = Instructions::Extern;
                 else error("Unexpected token: " + i);
             } else {
                 Types type = getType(i);