From fa8891ffe017ae890f0ef07915cf8b52acd7304a Mon Sep 17 00:00:00 2001
From: ubq323 <ubq323@ubq323.website>
Date: Thu, 20 Jun 2024 21:45:57 +0100
Subject: add true, false, nil keywords

---
 com.c | 18 +++++++++++++-----
 dis.c |  4 ++++
 val.c |  5 +++++
 val.h |  1 +
 vm.c  | 10 +++++++++-
 vm.h  |  6 +++++-
 6 files changed, 37 insertions(+), 7 deletions(-)

diff --git a/com.c b/com.c
index 4252ecd..3d891f7 100644
--- a/com.c
+++ b/com.c
@@ -10,10 +10,18 @@
 static void compile_node(State *S, Chunk *ch, AstNode a) {
 	switch (a.ty) {
 	case AST_IDENT:;
-		size_t len = strlen(a.as.str);
-		ObjString *o = objstring_copy(S, a.as.str, len);
-		chunk_wbc(S, ch, OP_GETGLOBAL);
-		chunk_wbc(S, ch, chunk_wconst(S, ch, VAL_OBJ(o)));
+		char *ident = a.as.str;
+
+		if (0 == strcmp(ident, "true")) chunk_wbc(S, ch, OP_TRUE);
+		else if (0 == strcmp(ident, "false")) chunk_wbc(S, ch, OP_FALSE);
+		else if (0 == strcmp(ident, "nil")) chunk_wbc(S, ch, OP_NIL);
+		else {
+			// global read
+			size_t len = strlen(a.as.str);
+			ObjString *o = objstring_copy(S, a.as.str, len);
+			chunk_wbc(S, ch, OP_GETGLOBAL);
+			chunk_wbc(S, ch, chunk_wconst(S, ch, VAL_OBJ(o)));
+		}
 		break;
 	case AST_NUM:
 		chunk_wbc(S, ch, OP_LOADK);
@@ -104,6 +112,6 @@ int main() {
 	chunk_wbc(S, &ch, OP_PRINT);
 	chunk_wbc(S, &ch, OP_RET);
 
-	runvm(S);
+	return runvm(S);
 }
 
diff --git a/dis.c b/dis.c
index 0fb23f8..c4492df 100644
--- a/dis.c
+++ b/dis.c
@@ -44,6 +44,10 @@ void disasm_chunk(Chunk *ch) {
 		SIMPLE_INSTR(OP_SUB, "sub")
 		SIMPLE_INSTR(OP_MUL, "mul")
 		SIMPLE_INSTR(OP_DIV, "div")
+		SIMPLE_INSTR(OP_NIL, "nil")
+		SIMPLE_INSTR(OP_TRUE, "true")
+		SIMPLE_INSTR(OP_FALSE, "false")
+
 		}
 	}
 #undef SIMPLE_INSTR
diff --git a/val.c b/val.c
index 40b7c5b..6f1dd9e 100644
--- a/val.c
+++ b/val.c
@@ -19,6 +19,11 @@ ObjString *objstring_copy(State *S, char *src, size_t len) {
 	return objstring_create(S, d, len, hash);
 }
 
+ObjString *objstring_copy_cstr(State *S, char *str) {
+	size_t len = strlen(str);
+	return objstring_copy(S, str, len);
+}
+
 ObjString *objstring_take(State *S, char *src, size_t len) { 
 	uint32_t hash = hash_string(src, len);
 	ObjString *interned = ht_findstring(S, &S->strings, src, len, hash);
diff --git a/val.h b/val.h
index 4c84fd9..db0a789 100644
--- a/val.h
+++ b/val.h
@@ -49,6 +49,7 @@ typedef struct {
 // Constructs a new objstring from the given C string,
 // creating its own fresh copy of the data.
 ObjString *objstring_copy(State *S, char *src, size_t len);
+ObjString *objstring_copy_cstr(State *s, char *str);
 // Constructs a new objstring from the given C string,
 // taking ownership of the provided data.
 ObjString *objstring_take(State *S, char *src, size_t len);
diff --git a/vm.c b/vm.c
index 9f6ece6..205e0fd 100644
--- a/vm.c
+++ b/vm.c
@@ -46,10 +46,12 @@ Thread thread_new(State *S) {
 }
 
 
-void runvm(State *S) {
+int runvm(State *S) {
 	Thread *th = S->th;
 	Chunk *ch = th->ch;
 
+	int status = 1;
+
 	disasm_chunk(ch);
 
 #define RBYTE() (ch->bc.d[th->ip++])
@@ -63,6 +65,7 @@ void runvm(State *S) {
 		uint8_t instr = RBYTE();
 		switch (instr) {
 		case OP_RET:
+			status  = 0;
 			printf("done!\n");
 			goto done;
 			break;
@@ -127,10 +130,15 @@ void runvm(State *S) {
 			ARITH_OP(OP_DIV, /)
 #undef ARITH_OP
 
+		case OP_NIL: PUSH(VAL_NIL); break;
+		case OP_TRUE: PUSH(VAL_TRUE); break;
+		case OP_FALSE: PUSH(VAL_FALSE); break;
+
 
 		}
 	}
 	done:;
+	return status;
 }
 
 
diff --git a/vm.h b/vm.h
index 859e207..e184426 100644
--- a/vm.h
+++ b/vm.h
@@ -49,8 +49,12 @@ typedef enum {
 
 	OP_GETGLOBAL,
 	OP_SETGLOBAL,
+
+	OP_TRUE,
+	OP_FALSE,
+	OP_NIL,
 } Op;
 
-void runvm(State *S);
+int runvm(State *S);
 
 #endif
-- 
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