From 9ce9a7f510e6ba407c2e14d3eae4d603b38edde7 Mon Sep 17 00:00:00 2001
From: Bad Diode <bd@badd10de.dev>
Date: Fri, 22 Oct 2021 13:58:02 +0200
Subject: Prepare compilation pipeline

---
 src/bytecode/compiler.h | 34 ++++++++++++++++++++++++++++++++++
 src/bytecode/main.c     | 30 +++++++++++++-----------------
 src/bytecode/vm.h       | 35 ++++++++++++++++++++---------------
 3 files changed, 67 insertions(+), 32 deletions(-)
 create mode 100644 src/bytecode/compiler.h

(limited to 'src/bytecode')

diff --git a/src/bytecode/compiler.h b/src/bytecode/compiler.h
new file mode 100644
index 0000000..283d7a6
--- /dev/null
+++ b/src/bytecode/compiler.h
@@ -0,0 +1,34 @@
+#ifndef BDL_COMPILER_H
+#define BDL_COMPILER_H
+
+#include "chunk.h"
+#include "lexer.h"
+
+typedef struct Visitor {
+    Token *tokens;
+    size_t current;
+} Visitor;
+
+// Mimics the functionality in the Scanner functions, but for entire tokens.
+Token next_token(Visitor *visitor);
+Token peek_token(const Visitor *visitor);
+bool has_next_token(const Visitor *visitor);
+
+Chunk * compile(Token *tokens);
+
+Chunk *
+compile(Token *tokens) {
+    Chunk *chunk = NULL;
+    chunk = chunk_init();
+    size_t const_a = add_constant(chunk, 7);
+    add_code(chunk, OP_CONSTANT, 1, 1);
+    add_code(chunk, const_a, 1, 1);
+    size_t const_b = add_constant(chunk, 2);
+    add_code(chunk, OP_CONSTANT, 1, 2);
+    add_code(chunk, const_b, 1, 2);
+    add_code(chunk, OP_MOD, 1, 3);
+    add_code(chunk, OP_RETURN, 1, 1);
+    return chunk;
+}
+
+#endif // BDL_COMPILER_H
diff --git a/src/bytecode/main.c b/src/bytecode/main.c
index 5661747..d6cb5d3 100644
--- a/src/bytecode/main.c
+++ b/src/bytecode/main.c
@@ -11,6 +11,7 @@
 #define DEBUG_TRACE_EXECUTION
 
 #include "vm.h"
+#include "compiler.h"
 #include "ops.h"
 #include "debug.h"
 #include "errors.c"
@@ -22,43 +23,38 @@ static VM vm;
 
 void
 init(void) {
-    vm = vm_init();
+    vm_init(&vm);
 }
 
 void
 halt(void) {
-    vm_free(vm);
+    vm_free(&vm);
 }
 
 void
 process_source(const StringView *source) {
+    // Read tokens.
     Token *tokens = tokenize(source);
     if (errors_n != 0) {
         array_free(tokens);
         return;
     }
 
-    for (size_t i = 0; i < array_size(tokens); i++) {
-        print_token(tokens[i]);
+    // Compile chunk.
+    Chunk *chunk = compile(tokens);
+    if (errors_n != 0) {
+        chunk_free(chunk);
+        array_free(tokens);
+        return;
     }
 
-    size_t const_a = add_constant(vm.chunk, 7);
-    add_code(vm.chunk, OP_CONSTANT, 1, 1);
-    add_code(vm.chunk, const_a, 1, 1);
-    size_t const_b = add_constant(vm.chunk, 2);
-    add_code(vm.chunk, OP_CONSTANT, 1, 2);
-    add_code(vm.chunk, const_b, 1, 2);
-
-    // Arithmetic.
-    add_code(vm.chunk, OP_MOD, 1, 3);
-
-    add_code(vm.chunk, OP_RETURN, 1, 1);
-
-    vm_interpret(vm);
+    // Interpret chunk.
+    vm_interpret(vm, chunk);
     if (errors_n != 0) {
         disassemble_chunk(vm.chunk, "test chunk");
     }
 
+    chunk_free(chunk);
     array_free(tokens);
 }
 
diff --git a/src/bytecode/vm.h b/src/bytecode/vm.h
index 6c5dfa7..f9e64d1 100644
--- a/src/bytecode/vm.h
+++ b/src/bytecode/vm.h
@@ -18,27 +18,33 @@ typedef struct VM {
     Object *stack;
 } VM;
 
-VM vm_init(void);
-void vm_free(VM vm);
-void vm_interpret(VM vm);
+void vm_init(VM *vm);
+void vm_free(VM *vm);
+void vm_reset(VM *vm);
+void vm_interpret(VM vm, Chunk *chunk);
 
-VM
-vm_init(void) {
-    VM vm = {
-        .chunk = chunk_init(),
-    };
-    array_init(vm.stack, VM_STACK_CAP);
-    return vm;
+void
+vm_init(VM *vm) {
+    *vm = (VM){0};
+    array_init(vm->stack, VM_STACK_CAP);
+}
+
+void
+vm_free(VM *vm) {
+    array_free(vm->stack);
 }
 
 void
-vm_free(VM vm) {
-    chunk_free(vm.chunk);
-    array_free(vm.stack);
+vm_reset(VM *vm) {
+    vm_free(vm);
+    vm_init(vm);
 }
 
 void
-vm_interpret(VM vm) {
+vm_interpret(VM vm, Chunk *chunk) {
+    vm.chunk = chunk;
+    vm.pc = vm.chunk->code;
+
     if (vm.chunk->code == NULL || array_size(vm.chunk->code) == 0) {
         error_push((Error){
             .type = ERR_TYPE_RUNTIME,
@@ -47,7 +53,6 @@ vm_interpret(VM vm) {
         return;
     }
 
-    vm.pc = vm.chunk->code;
     u8 *last = vm.chunk->code + array_size(vm.chunk->code);
     while (vm.pc < last) {
 #ifdef DEBUG_TRACE_EXECUTION
-- 
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