From 7717a40574d41fc85d249ac78ae8faad7a6097bf Mon Sep 17 00:00:00 2001
From: DiamondNether90 <diamondnether941@gmail.com>
Date: Mon, 19 Jan 2026 21:14:48 +1100
Subject: [PATCH] Error function

---
 src/interpreter.c | 31 ++++++++++++++++++++++++++++++-
 src/parser.c      |  1 +
 src/types.c       |  3 +++
 src/types.h       |  2 +-
 tests/error.grnd  |  2 ++
 5 files changed, 37 insertions(+), 2 deletions(-)
 create mode 100644 tests/error.grnd

diff --git a/src/interpreter.c b/src/interpreter.c
index 5e6ac0a..07f73f3 100644
--- a/src/interpreter.c
+++ b/src/interpreter.c
@@ -13,6 +13,23 @@ int currentInstruction = 0;
 
 bool isMainScopeGlobal = true;
 
+[[noreturn]] void customError(GroundArg type, GroundArg what, GroundInstruction* where, int whereLine, int exitCode) {
+    printf("Ground runtime error:\n  ErrorType: ");
+    printGroundArg(&type);
+    printf("\n  ErrorContext: ");
+    printGroundArg(&what);
+    printf("\n");
+    if (where != NULL) {
+        printf("  ErrorInstruction: ");
+        printGroundInstruction(where);
+        printf("\n");
+    }
+    if (whereLine > -1) {
+        printf("  ErrorLine: %d\n", whereLine + 1);
+    }
+    exit(exitCode);
+}
+
 [[noreturn]] void runtimeError(GroundRuntimeError error, char* what, GroundInstruction* where, int whereLine) {
     printf("Ground runtime error:\n  ErrorType: ");
     switch (error) {
@@ -813,7 +830,19 @@ GroundValue interpretGroundInstruction(GroundInstruction inst, GroundScope* scop
             }
             break;
         }
-
+        case ERRORCMD: {
+            if (in->args.length < 3) {
+                runtimeError(TOO_FEW_ARGS, "Expecting 3 args", in, currentInstruction);
+            } else if (in->args.length > 3) {
+                runtimeError(TOO_MANY_ARGS, "Expecting 3 args", in, currentInstruction);
+            }
+            if (in->args.args[2].value.value.type != INT ) {
+                runtimeError(ARG_TYPE_MISMATCH, "Expecting an int for arg 2", in, currentInstruction);
+            }
+            
+            customError(in->args.args[0], in->args.args[1], in, currentInstruction, in->args.args[2].value.value.data.intVal);
+            break;
+        }
         /*
          * VARIABLES AND LISTS
          * These instructions are for initializing variables and lists.
diff --git a/src/parser.c b/src/parser.c
index d956934..57a3395 100644
--- a/src/parser.c
+++ b/src/parser.c
@@ -137,6 +137,7 @@ static GroundInstType getInstructionType(const char* inst) {
     if (strcmp(inst, "input") == 0 || strcmp(inst, "stdin") == 0) return INPUT;
     if (strcmp(inst, "print") == 0 || strcmp(inst, "stdout") == 0) return PRINT;
     if (strcmp(inst, "println") == 0 || strcmp(inst, "stdlnout") == 0) return PRINTLN;
+    if (strcmp(inst, "error") == 0) return ERRORCMD;
     if (strcmp(inst, "set") == 0) return SET;
     if (strcmp(inst, "gettype") == 0) return GETTYPE;
     if (strcmp(inst, "exists") == 0) return EXISTS;
diff --git a/src/types.c b/src/types.c
index 01becb4..334a466 100644
--- a/src/types.c
+++ b/src/types.c
@@ -412,6 +412,9 @@ void printGroundInstruction(GroundInstruction* gi) {
             break;
         case CREATELABEL:
             break;
+        case ERRORCMD:
+            printf("error");
+            break;
         default:
             printf("FIXME");
             break;
diff --git a/src/types.h b/src/types.h
index 0b3c903..65690dc 100644
--- a/src/types.h
+++ b/src/types.h
@@ -9,7 +9,7 @@
 #include "include/uthash.h"
 
 typedef enum GroundInstType {
-    IF, JUMP, END, INPUT, PRINT, PRINTLN, SET, GETTYPE, EXISTS, SETLIST, SETLISTAT, GETLISTAT, GETLISTSIZE, LISTAPPEND, GETSTRSIZE, GETSTRCHARAT, ADD, SUBTRACT, MULTIPLY, DIVIDE, EQUAL, INEQUAL, NOT, GREATER, LESSER, STOI, STOD, TOSTRING, FUN, RETURN, ENDFUN, PUSHARG, CALL, STRUCT, ENDSTRUCT, INIT, USE, EXTERN, CREATELABEL, PAUSE, DROP
+    IF, JUMP, END, INPUT, PRINT, PRINTLN, SET, GETTYPE, EXISTS, SETLIST, SETLISTAT, GETLISTAT, GETLISTSIZE, LISTAPPEND, GETSTRSIZE, GETSTRCHARAT, ADD, SUBTRACT, MULTIPLY, DIVIDE, EQUAL, INEQUAL, NOT, GREATER, LESSER, STOI, STOD, TOSTRING, FUN, RETURN, ENDFUN, PUSHARG, CALL, STRUCT, ENDSTRUCT, INIT, USE, EXTERN, CREATELABEL, PAUSE, DROP, ERRORCMD
 } GroundInstType;
 
 typedef enum GroundValueType {
diff --git a/tests/error.grnd b/tests/error.grnd
new file mode 100644
index 0000000..460bb30
--- /dev/null
+++ b/tests/error.grnd
@@ -0,0 +1,2 @@
+setlist &dat 1 2 3 "Hi!"
+error "Hello" $dat 1
-- 
2.47.3