Add string operations

README.md

@@ -25,13 +25,13 @@ Progress marker:
     - [x] Labels
     - [x] Console I/O
     - [x] Control flow
-    - [ ] Data
+    - [x] Data
         - [x] Variable creation
         - [x] Variable access
-        - [ ] Lists
+        - [x] Lists
-            - [ ] Creation
+            - [x] Creation
-            - [ ] Access
+            - [x] Access
-        - [ ] String operations
+        - [x] String operations
     - [x] Maths
     - [x] Comparisions
     - [ ] Type conversions

src/interpreter.c

@@ -697,6 +697,54 @@ void interpretGroundInstruction(GroundInstruction inst, GroundScope* scope) {
             break;
         }
         
+        /*
+         * STRING OPERATIONS 
+         * Allows easier manipulation of strings.
+         * Instructions: 
+         *    getstrcharat, getstrsize
+        */
+        case GETSTRCHARAT: {
+            if (in->args.length < 3) {
+                runtimeError(TOO_FEW_ARGS, "Expecting 3 args", in, currentInstruction);
+            }
+            if (in->args.length > 3) {
+                runtimeError(TOO_MANY_ARGS, "Expecting 3 args", in, currentInstruction);
+            }
+            if (in->args.args[0].type != VALUE && in->args.args[0].value.value.type != STRING) {
+                runtimeError(ARG_TYPE_MISMATCH, "Expecting a String for arg 1", in, currentInstruction);
+            }
+            if (in->args.args[1].type != VALUE && in->args.args[1].value.value.type != INT) {
+                runtimeError(ARG_TYPE_MISMATCH, "Expecting an Int for arg 2", in, currentInstruction);
+            }
+            if (in->args.args[2].type != DIRREF) {
+                runtimeError(ARG_TYPE_MISMATCH, "Expecting a DirectRef for arg 3", in, currentInstruction);
+            }
+            char* str = in->args.args[0].value.value.data.stringVal;
+            int64_t idx = in->args.args[1].value.value.data.intVal;
+            if (idx < strlen(str)) {
+                addVariable(scope->variables, in->args.args[2].value.refName, createCharGroundValue(str[idx]));
+            } else {
+                runtimeError(STRING_ERROR, "Out of bounds index", in, currentInstruction);
+            }
+            break;
+        }
+        case GETSTRSIZE: {
+            if (in->args.length < 2) {
+                runtimeError(TOO_FEW_ARGS, "Expecting 2 args", in, currentInstruction);
+            }
+            if (in->args.length > 2) {
+                runtimeError(TOO_MANY_ARGS, "Expecting 2 args", in, currentInstruction);
+            }
+            if (in->args.args[0].type != VALUE && in->args.args[0].value.value.type != STRING) {
+                runtimeError(ARG_TYPE_MISMATCH, "Expecting a String for arg 1", in, currentInstruction);
+            }
+            if (in->args.args[1].type != DIRREF) {
+                runtimeError(ARG_TYPE_MISMATCH, "Expecting a DirectRef for arg 2", in, currentInstruction);
+            }
+            addVariable(scope->variables, in->args.args[1].value.refName, createIntGroundValue(strlen(in->args.args[0].value.value.data.stringVal)));
+            break;
+        }
+
         /*
          * COMPARISONS
          * Allows comparing values.

src/interpreter.h

@@ -7,7 +7,7 @@
 #include "include/uthash.h"
 
 typedef enum GroundRuntimeError {
-    ARG_TYPE_MISMATCH, TOO_FEW_ARGS, TOO_MANY_ARGS, UNKNOWN_LABEL, UNKNOWN_VARIABLE, LIST_ERROR, FIXME 
+    ARG_TYPE_MISMATCH, TOO_FEW_ARGS, TOO_MANY_ARGS, UNKNOWN_LABEL, UNKNOWN_VARIABLE, LIST_ERROR, STRING_ERROR, FIXME 
 } GroundRuntimeError;
 
 typedef struct GroundLabel {

tests/string.grnd

@@ -0,0 +1,11 @@
+input &str
+getstrsize $str &size
+set &idx 0
+@loop
+getstrcharat $str $idx &char
+println $char
+add 1 $idx &idx
+equal $idx $size &cond
+if $cond %loopend
+jump %loop
+@loopend