src/interpreter.c

@@ -11,7 +11,7 @@
 
 int currentInstruction = 0;
 
-void runtimeError(GroundRuntimeError error, char* what, GroundInstruction* where, int whereLine) {
+[[noreturn]] void runtimeError(GroundRuntimeError error, char* what, GroundInstruction* where, int whereLine) {
     printf("Ground runtime error:\n  ErrorType: ");
     switch (error) {
         case ARG_TYPE_MISMATCH: {
@@ -46,6 +46,18 @@ void runtimeError(GroundRuntimeError error, char* what, GroundInstruction* where
             printf("MathError");
             break;
         }
+        case RETURN_TYPE_MISMATCH: {
+            printf("ReturnTypeMismatch");
+            break;
+        }
+        case PREMATURE_EOF: {
+            printf("PrematureEof");
+            break;
+        }
+        case INVALID_INSTRUCTION: {
+            printf("InvalidInstruction");
+            break;
+        }
         default:
         case FIXME: {
             printf("FIXME (please report issue to https://chsp.au/ground/cground)");
@@ -173,7 +185,7 @@ GroundDebugInstruction parseDebugInstruction(char* in) {
         }
     }
 
-    if (spacepos == -1) {
+    if (spacepos == (size_t) -1) {
         spacepos = insize;
     }
 
@@ -234,6 +246,186 @@ void groundAddNativeFunction(GroundScope* scope, char* name, NativeGroundFunctio
     addVariable(scope->variables, name, createFunctionGroundValue(gf));
 }
 
+GroundFunction* parseFunction(GroundProgram* in, size_t errorOffset) {
+    GroundFunction* function = createGroundFunction();
+    for (size_t i = 0; i < in->size; i++) {
+        if (in->instructions[i].args.length < 2) {
+            function->returnType = NONE;
+        } else {
+            if (in->instructions[i].args.args[1].type != TYPEREF) {
+                runtimeError(ARG_TYPE_MISMATCH, "Expecting a TypeRef for arg 2", &in->instructions[i], errorOffset + i);
+            }
+            GroundArg* args = in->instructions[i].args.args;
+            function->returnType = stringToValueType(args[1].value.refName);
+            size_t length = in->instructions[i].args.length;
+            for (size_t j = 2; j < length; j += 2) {
+                if (args[j].type != TYPEREF) {
+                    runtimeError(ARG_TYPE_MISMATCH, "Expecting a TypeRef", &in->instructions[i], errorOffset + i);
+                }
+                if (j + 1 >= length) {
+                    runtimeError(TOO_FEW_ARGS, "Expecting a DirectRef after a TypeRef", &in->instructions[i], errorOffset + i);
+                }
+                if (args[j + 1].type != DIRREF) {
+                    runtimeError(ARG_TYPE_MISMATCH, "Expecting a DirectRef after a TypeRef", &in->instructions[i], errorOffset + i);
+                }
+                addArgsToGroundFunction(function, stringToValueType(args[j].value.refName), args[j + 1].value.refName);
+            }
+        }
+        i++;
+        while (i < in->size) {
+            addInstructionToProgram(&function->program, in->instructions[i]);
+            i++;
+        }
+        break;
+    }
+    return function;
+}
+
+GroundStruct parseStruct(GroundProgram* in, GroundScope* scope, size_t errorOffset) {
+    GroundStruct gstruct = createStruct();
+    for (size_t i = 0; i < in->size; i++) {
+        switch (in->instructions[i].type) {
+            case SET: {
+                if (in->instructions[i].args.length < 2) {
+                    runtimeError(TOO_FEW_ARGS, "Expecting 2 args", &in->instructions[i], i + errorOffset);
+                }
+                if (in->instructions[i].args.length > 2) {
+                    runtimeError(TOO_MANY_ARGS, "Expecting 2 args", &in->instructions[i], i + errorOffset);
+                }
+                if (in->instructions[i].args.args[0].type != DIRREF) {
+                    runtimeError(ARG_TYPE_MISMATCH, "Expecting a DirectRef for arg 1", &in->instructions[i], i + errorOffset);
+                }
+                if (in->instructions[i].args.args[1].type != VALUE) {
+                    runtimeError(ARG_TYPE_MISMATCH, "Expecting a Value for arg 2", &in->instructions[i], i + errorOffset);
+                }
+                addFieldToStruct(&gstruct, in->instructions[i].args.args[0].value.refName, in->instructions[i].args.args[1].value.value);
+                break;
+            }
+            case INIT: {
+                if (in->instructions[i].args.length < 2) {
+                    runtimeError(TOO_FEW_ARGS, "Expecting 2 args", &in->instructions[i], currentInstruction);
+                }
+                if (in->instructions[i].args.length > 2) {
+                    runtimeError(TOO_MANY_ARGS, "Expecting 2 args", &in->instructions[i], currentInstruction);
+                }
+                if (in->instructions[i].args.args[0].type != DIRREF) {
+                    runtimeError(ARG_TYPE_MISMATCH, "Expecting a DirectRef for arg 1", &in->instructions[i], currentInstruction);
+                }
+                if (in->instructions[i].args.args[1].type != TYPEREF) {
+                    runtimeError(ARG_TYPE_MISMATCH, "Expecting a TypeRef for arg 2", &in->instructions[i], currentInstruction);
+                }
+
+                GroundValue gv;
+
+                switch (stringToValueType(in->instructions[i].args.args[0].value.refName)) {
+                    case INT: {
+                        gv = createIntGroundValue(0);
+                        break;
+                    }
+                    case DOUBLE: {
+                        gv = createDoubleGroundValue(0);
+                        break;
+                    }
+                    case STRING: {
+                        gv = createStringGroundValue("");
+                        break;
+                    }
+                    case CHAR: {
+                        gv = createCharGroundValue('\0');
+                        break;
+                    }
+                    case BOOL: {
+                        gv = createBoolGroundValue(false);
+                        break;
+                    }
+                    case LIST: {
+                        gv = createListGroundValue(createList());
+                        break;
+                    }
+                    case FUNCTION: {
+                        gv = createFunctionGroundValue(createGroundFunction());
+                        break;
+                    }
+                    case STRUCTVAL: {
+                        gv.type = STRUCTVAL;
+                        gv.data.structVal = malloc(sizeof(GroundStruct));
+                        *gv.data.structVal = createStruct();
+                        break;
+                    }
+                    case CUSTOM: {
+                        GroundVariable* var = findVariable(*scope->variables, in->instructions[i].args.args[1].value.refName);
+                        if (var == NULL) {
+                            runtimeError(UNKNOWN_VARIABLE, "Couldn't find the specified type", &in->instructions[i], currentInstruction);
+                        }
+                        if (var->value.type != STRUCTVAL) {
+                            runtimeError(ARG_TYPE_MISMATCH, "TypeRef does not reference a struct", &in->instructions[i], currentInstruction);
+                        }
+                        GroundStruct* gstruct = var->value.data.structVal;
+                        gv.type = CUSTOM;
+                        gv.data.customVal = malloc(sizeof(GroundObject));
+                        *gv.data.customVal = createObject(*gstruct);
+                        break;
+                    }
+                    case NONE: {
+                        gv.type = NONE;
+                        break;
+                    }
+                    default: {
+                        runtimeError(FIXME, "Reached should-be-impossible state", &in->instructions[i], currentInstruction);
+                        break;
+                    }
+                }
+                addFieldToStruct(&gstruct, in->instructions[i].args.args[0].value.refName, gv);
+
+                break;
+            }
+            case FUN: {
+                if (in->instructions[i].args.length < 1) {
+                    runtimeError(TOO_FEW_ARGS, "Expecting 1 or more args", &in->instructions[i], i);
+                }
+                if (in->instructions[i].args.args[0].type != FNREF) {
+                    runtimeError(ARG_TYPE_MISMATCH, "Expecting a FunctionRef for arg 1", &in->instructions[i], i);
+                }
+                char* name = malloc(strlen(in->instructions[i].args.args[0].value.refName) + 1);
+                strcpy(name, in->instructions[i].args.args[0].value.refName);
+
+                size_t counter = 1;
+                GroundProgram gp = createGroundProgram();
+                addInstructionToProgram(&gp, in->instructions[i]);
+                size_t errorOffset = i;
+                i++;
+                while (counter > 0) {
+                    if (i >= in->size) {
+                        runtimeError(PREMATURE_EOF, "Reached end of scope before function definition ended", &in->instructions[i - 1], i - 1);
+                    }
+                    if (in->instructions[i].type == FUN) {
+                        counter++;
+                    }
+                    if (in->instructions[i].type == ENDFUN) {
+                        counter--;
+                    }
+                    addInstructionToProgram(&gp, in->instructions[i]);
+                    i++;
+                }
+
+                GroundFunction* function = parseFunction(&gp, errorOffset);
+                function->startLine = i;
+                GroundValue gv = createFunctionGroundValue(function);
+                addFieldToStruct(&gstruct, name, gv);
+                break;
+            }
+            case ENDSTRUCT: {
+                break;
+            }
+            default: {
+                runtimeError(INVALID_INSTRUCTION, "Unsupported instruction while inside struct", &in->instructions[i], errorOffset + i);
+            }
+
+        }
+    }
+    return gstruct;
+}
+
 GroundValue interpretGroundProgram(GroundProgram* in, GroundScope* inScope) {
     GroundLabel* labels = NULL;
     GroundVariable* variables = NULL;
@@ -246,52 +438,87 @@ GroundValue interpretGroundProgram(GroundProgram* in, GroundScope* inScope) {
         scope.labels = &labels;
         scope.variables = &variables;
     }
-    // Preprocess all labels and functions
+    // Preprocess all labels, structs and functions
-    for (int i = 0; i < in->size; i++) {
+    for (size_t i = 0; i < in->size; i++) {
         if (in->instructions[i].type == CREATELABEL) {
             addLabel(scope.labels, in->instructions[i].args.args[0].value.refName, i);
         }
         if (in->instructions[i].type == FUN) {
-            GroundFunction* function = createGroundFunction();
-            function->startLine = i;
             if (in->instructions[i].args.length < 1) {
                 runtimeError(TOO_FEW_ARGS, "Expecting 1 or more args", &in->instructions[i], i);
             }
             if (in->instructions[i].args.args[0].type != FNREF) {
                 runtimeError(ARG_TYPE_MISMATCH, "Expecting a FunctionRef for arg 1", &in->instructions[i], i);
             }
-            char* functionName = in->instructions[i].args.args[0].value.refName;
+            char* name = malloc(strlen(in->instructions[i].args.args[0].value.refName) + 1);
-            if (in->instructions[i].args.length < 2) {
+            strcpy(name, in->instructions[i].args.args[0].value.refName);
-                function->returnType = NONE;
+
-            } else {
+            size_t counter = 1;
-                if (in->instructions[i].args.args[1].type != TYPEREF) {
+            GroundProgram gp = createGroundProgram();
-                    runtimeError(ARG_TYPE_MISMATCH, "Expecting a TypeRef for arg 2", &in->instructions[i], i);
+            addInstructionToProgram(&gp, in->instructions[i]);
-                }
+            size_t errorOffset = i;
-                GroundArg* args = in->instructions[i].args.args;
-                function->returnType = stringToValueType(args[1].value.refName);
-                size_t length = in->instructions[i].args.length;
-                for (size_t j = 2; j < length; j += 2) {
-                    if (args[j].type != TYPEREF) {
-                        runtimeError(ARG_TYPE_MISMATCH, "Expecting a TypeRef", &in->instructions[i], i);
-                    }
-                    if (j + 1 >= length) {
-                        runtimeError(TOO_FEW_ARGS, "Expecting a DirectRef after a TypeRef", &in->instructions[i], i);
-                    }
-                    if (args[j + 1].type != DIRREF) {
-                        runtimeError(ARG_TYPE_MISMATCH, "Expecting a DirectRef after a TypeRef", &in->instructions[i], i);
-                    }
-                    addArgsToGroundFunction(function, stringToValueType(args[j].value.refName), args[j + 1].value.refName);
-                }
-            }
             i++;
-            while (in->instructions[i].type != ENDFUN) {
+            while (counter > 0) {
-                addInstructionToProgram(&function->program, in->instructions[i]);
+                if (i >= in->size) {
+                    runtimeError(PREMATURE_EOF, "Reached end of scope before function definition ended", &in->instructions[i - 1], i - 1);
+                }
+                if (in->instructions[i].type == FUN) {
+                    counter++;
+                }
+                if (in->instructions[i].type == ENDFUN) {
+                    counter--;
+                }
+                addInstructionToProgram(&gp, in->instructions[i]);
                 i++;
             }
-            addVariable(scope.variables, functionName, createFunctionGroundValue(function));
+
+            GroundFunction* function = parseFunction(&gp, errorOffset);
+            function->startLine = i;
+            GroundValue gv = createFunctionGroundValue(function);
+
+            addVariable(scope.variables, name, gv);
+        }
+        if (in->instructions[i].type == STRUCT) {
+            if (in->instructions[i].args.length < 1) {
+                runtimeError(TOO_FEW_ARGS, "Expecting 1 arg", &in->instructions[i], i);
+            }
+            if (in->instructions[i].args.length > 1) {
+                runtimeError(TOO_MANY_ARGS, "Expecting 1 arg", &in->instructions[i], i);
+            }
+            if (in->instructions[i].args.args[0].type != TYPEREF) {
+                runtimeError(ARG_TYPE_MISMATCH, "Expected arg 1 to be a typeref", &in->instructions[i], i);
+            }
+            char* name = malloc(strlen(in->instructions[i].args.args[0].value.refName) + 1);
+            strcpy(name, in->instructions[i].args.args[0].value.refName);
+            i++;
+
+            size_t counter = 1;
+            GroundProgram gp = createGroundProgram();
+            size_t errorOffset = i;
+            while (counter > 0) {
+                if (i >= in->size) {
+                    runtimeError(PREMATURE_EOF, "Reached end of scope before struct definition ended", &in->instructions[i - 1], i - 1);
+                }
+                if (in->instructions[i].type == STRUCT) {
+                    counter++;
+                }
+                if (in->instructions[i].type == ENDSTRUCT) {
+                    counter--;
+                }
+                addInstructionToProgram(&gp, in->instructions[i]);
+                i++;
+            }
+
+            GroundValue gv = {
+                .type = STRUCTVAL,
+                .data.structVal = malloc(sizeof(GroundStruct))
+            };
+            *gv.data.structVal = parseStruct(&gp, &scope, errorOffset);
+
+            addVariable(scope.variables, name, gv);
         }
     }
-    for (int i = 0; i < in->size; i++) {
+    for (size_t i = 0; i < in->size; i++) {
         if (in->instructions[i].type == FUN) {
             int count = 1;
             while (count > 0) {
@@ -307,6 +534,21 @@ GroundValue interpretGroundProgram(GroundProgram* in, GroundScope* inScope) {
                 }
             }
         }
+        if (in->instructions[i].type == STRUCT) {
+            int count = 1;
+            while (count > 0) {
+                i++;
+                if (i >= in->size) {
+                    return createNoneGroundValue();
+                }
+                if (in->instructions[i].type == STRUCT) {
+                    count++;
+                }
+                if (in->instructions[i].type == ENDSTRUCT) {
+                    count--;
+                }
+            }
+        }
         if (in->instructions[i].type == PAUSE || instructionsToPause == 0) {
             printf("Paused execution\n");
             printf("Previous instruction: ");
@@ -428,7 +670,7 @@ GroundValue interpretGroundInstruction(GroundInstruction inst, GroundScope* scop
     GroundInstruction* in = &copied_inst;
 
     // Insert variables prefixed with $
-    for (int i = 0; i < in->args.length; i++) {
+    for (size_t i = 0; i < in->args.length; i++) {
         if (in->args.args[i].type == VALREF) {
             GroundVariable* variable = findVariable(*scope->variables, in->args.args[i].value.refName);
             if (variable) {
@@ -441,9 +683,11 @@ GroundValue interpretGroundInstruction(GroundInstruction inst, GroundScope* scop
         }
     }
     switch (in->type) {
-        // We can safely ignore any CREATELABEL, FUN, and ENDFUN instructions, these have been preprocessed
+        // We can safely ignore these instructions, as they have been preprocessed
         case FUN:
         case ENDFUN:
+        case STRUCT:
+        case ENDSTRUCT:
         case CREATELABEL: {
             break;
         }
@@ -516,7 +760,7 @@ GroundValue interpretGroundInstruction(GroundInstruction inst, GroundScope* scop
             if (in->args.length < 1) {
                 runtimeError(TOO_FEW_ARGS, "Expecting 1 or more args", in, currentInstruction);
             }
-            for (int i = 0; i < in->args.length; i++) {
+            for (size_t i = 0; i < in->args.length; i++) {
                 if (i != 0) printf(" ");
                 printGroundArg(&in->args.args[i]);
             }
@@ -526,7 +770,7 @@ GroundValue interpretGroundInstruction(GroundInstruction inst, GroundScope* scop
             if (in->args.length < 1) {
                 runtimeError(TOO_FEW_ARGS, "Expecting 1 or more args", in, currentInstruction);
             }
-            for (int i = 0; i < in->args.length; i++) {
+            for (size_t i = 0; i < in->args.length; i++) {
                 if (i != 0) printf(" ");
                 printGroundArg(&in->args.args[i]);
             }
@@ -618,9 +862,15 @@ GroundValue interpretGroundInstruction(GroundInstruction inst, GroundScope* scop
                 }
                 case FUNCTION: {
                     addVariable(scope->variables, in->args.args[1].value.refName, createStringGroundValue("function"));
+                    break;
+                }
+                case STRUCTVAL: {
+                    addVariable(scope->variables, in->args.args[1].value.refName, createStringGroundValue("struct"));
+                    break;
                 }
                 case NONE: {
                     addVariable(scope->variables, in->args.args[1].value.refName, createStringGroundValue("none"));
+                    break;
                 }
             }
 
@@ -655,7 +905,7 @@ GroundValue interpretGroundInstruction(GroundInstruction inst, GroundScope* scop
                 runtimeError(ARG_TYPE_MISMATCH, "Expecting a DirectRef for arg 1", in, currentInstruction);
             }
             List newList = createList();
-            for (int i = 1; i < in->args.length; i++) {
+            for (size_t i = 1; i < in->args.length; i++) {
                 if (in->args.args[i].type != VALUE) {
                     runtimeError(ARG_TYPE_MISMATCH, "Expecting a Value for all args after arg 1", in, currentInstruction);
                 }
@@ -1132,7 +1382,7 @@ GroundValue interpretGroundInstruction(GroundInstruction inst, GroundScope* scop
                 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;
+            size_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 {
@@ -1628,6 +1878,87 @@ GroundValue interpretGroundInstruction(GroundInstruction inst, GroundScope* scop
             break;
         }
 
+        case INIT: {
+            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 != DIRREF) {
+                runtimeError(ARG_TYPE_MISMATCH, "Expecting a DirectRef for arg 1", in, currentInstruction);
+            }
+            if (in->args.args[1].type != TYPEREF) {
+                runtimeError(ARG_TYPE_MISMATCH, "Expecting a TypeRef for arg 2", in, currentInstruction);
+            }
+
+            GroundValue gv;
+
+            switch (stringToValueType(in->args.args[1].value.refName)) {
+                case INT: {
+                    gv = createIntGroundValue(0);
+                    break;
+                }
+                case DOUBLE: {
+                    gv = createDoubleGroundValue(0);
+                    break;
+                }
+                case STRING: {
+                    gv = createStringGroundValue("");
+                    break;
+                }
+                case CHAR: {
+                    gv = createCharGroundValue('\0');
+                    break;
+                }
+                case BOOL: {
+                    gv = createBoolGroundValue(false);
+                    break;
+                }
+                case LIST: {
+                    gv = createListGroundValue(createList());
+                    break;
+                }
+                case FUNCTION: {
+                    GroundFunction* gf = createGroundFunction();
+                    gf->returnType = NONE;
+                    gv = createFunctionGroundValue(gf);
+                    break;
+                }
+                case STRUCTVAL: {
+                    gv.type = STRUCTVAL;
+                    gv.data.structVal = malloc(sizeof(GroundStruct));
+                    *gv.data.structVal = createStruct();
+                    break;
+                }
+                case CUSTOM: {
+                    GroundVariable* var = findVariable(*scope->variables, in->args.args[1].value.refName);
+                    if (var == NULL) {
+                        runtimeError(UNKNOWN_VARIABLE, "Couldn't find the specified type", in, currentInstruction);
+                    }
+                    if (var->value.type != STRUCTVAL) {
+                        runtimeError(ARG_TYPE_MISMATCH, "TypeRef does not reference a struct", in, currentInstruction);
+                    }
+                    GroundStruct* gstruct = var->value.data.structVal;
+                    gv.type = CUSTOM;
+                    gv.data.customVal = malloc(sizeof(GroundObject));
+                    *gv.data.customVal = createObject(*gstruct);
+                    break;
+                }
+                case NONE: {
+                    gv.type = NONE;
+                    break;
+                }
+                default: {
+                    runtimeError(FIXME, "Reached should-be-impossible state", in, currentInstruction);
+                    break;
+                }
+            }
+            addVariable(scope->variables, in->args.args[0].value.refName, gv);
+
+            break;
+        }
+
         case DROP: {
             if (in->args.length < 1) {
                 runtimeError(TOO_FEW_ARGS, "Expecting 1 arg", in, currentInstruction);

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, STRING_ERROR, MATH_ERROR, RETURN_TYPE_MISMATCH, FIXME
+    ARG_TYPE_MISMATCH, TOO_FEW_ARGS, TOO_MANY_ARGS, UNKNOWN_LABEL, UNKNOWN_VARIABLE, LIST_ERROR, STRING_ERROR, MATH_ERROR, RETURN_TYPE_MISMATCH, PREMATURE_EOF, INVALID_INSTRUCTION, FIXME
 } GroundRuntimeError;
 
 typedef enum GroundDebugInstructionType {
@@ -36,8 +36,12 @@ typedef struct GroundDebugInstruction {
     char* arg;
 } GroundDebugInstruction;
 
+GroundStruct parseStruct(GroundProgram* in, GroundScope* scope, size_t errorOffset); 
+GroundFunction* parseFunction(GroundProgram* in, size_t errorOffset);
 GroundValue interpretGroundProgram(GroundProgram* in, GroundScope* inScope);
 GroundValue interpretGroundInstruction(GroundInstruction inst, GroundScope* scope);
 
 
+
+
 #endif

src/types.c

@@ -74,7 +74,7 @@ GroundValue copyGroundValue(const GroundValue* gv) {
             break;
         case LIST: {
             List newList = createList();
-            for (int i = 0; i < gv->data.listVal.size; i++) {
+            for (size_t i = 0; i < gv->data.listVal.size; i++) {
                 // Recursive call to handle nested lists and other types
                 appendToList(&newList, copyGroundValue(&gv->data.listVal.values[i]));
             }
@@ -93,6 +93,10 @@ GroundValue copyGroundValue(const GroundValue* gv) {
             // FIXME
             newGv.data.customVal = gv->data.customVal;
             break;
+        case NONE:
+        default: {
+
+        }
     }
     return newGv;
 }
@@ -125,7 +129,7 @@ void printGroundValue(GroundValue* gv) {
         }
         case LIST: {
             printf("[");
-            for (int i = 0; i < gv->data.listVal.size; i++) {
+            for (size_t i = 0; i < gv->data.listVal.size; i++) {
                 printGroundValue(&gv->data.listVal.values[i]);
                 if (i < gv->data.listVal.size - 1) {
                     printf(", ");
@@ -152,7 +156,7 @@ void freeGroundValue(GroundValue* gv) {
     }
     if (gv->type == LIST && gv->data.listVal.values != NULL) {
         List* list = &gv->data.listVal;
-        for (int i = 0; i < list->size; i++) {
+        for (size_t i = 0; i < list->size; i++) {
             freeGroundValue(&list->values[i]);
         }
         free(list->values);
@@ -394,7 +398,7 @@ void printGroundInstruction(GroundInstruction* gi) {
             break;
     }
     if (gi->type != CREATELABEL) printf(" ");
-    for (int i = 0; i < gi->args.length; i++) {
+    for (size_t i = 0; i < gi->args.length; i++) {
         if (gi->args.args[i].type == VALUE && gi->args.args[i].value.value.type == STRING) {
             printf("\"");
             printGroundArg(&gi->args.args[i]);
@@ -428,7 +432,7 @@ void appendToList(List* list, GroundValue value) {
     list->values[list->size - 1] = value;
 }
 
-ListAccess getListAt(List* list, int idx) {
+ListAccess getListAt(List* list, size_t idx) {
     if (list == NULL) {
         printf("Expecting a List ptr, got a null pointer instead.\nThis is likely not an error with your Ground program.\nPlease report this issue to https://chsp.au/ground/cground\n");
         exit(EXIT_FAILURE);
@@ -446,7 +450,7 @@ ListAccess getListAt(List* list, int idx) {
     }
 }
 
-ListAccessStatus setListAt(List* list, int idx, GroundValue value) {
+ListAccessStatus setListAt(List* list, size_t idx, GroundValue value) {
     if (list == NULL) {
         printf("Expecting a List ptr, got a null pointer instead.\nThis is likely not an error with your Ground program.\nPlease report this issue to https://chsp.au/ground/cground\n");
         exit(EXIT_FAILURE);

src/types.h

@@ -234,10 +234,10 @@ void appendToList(List* list, GroundValue value);
 
 // Gets item at index (idx) from list (list). If there is an error, it
 // will be indicated in the status field.
-ListAccess getListAt(List* list, int idx);
+ListAccess getListAt(List* list, size_t idx);
 
 // Sets an item in list (list) at index (idx) to GroundValue (value).
-ListAccessStatus setListAt(List* list, int idx, GroundValue value);
+ListAccessStatus setListAt(List* list, size_t idx, GroundValue value);
 
 // Creates a Ground struct
 GroundStruct createStruct();