Initial parser implementation that runs a simple hello_world.fun script.

CMakeLists.txt

@@ -7,8 +7,10 @@ set(CMAKE_C_STANDARD_REQUIRED ON)
 # Core VM/library sources
 add_library(fun_core
         src/bytecode.c
+        src/parser.c
         src/value.c
         src/vm.c
+        src/parser.c
 )
 
 target_include_directories(fun_core PUBLIC

src/fun.c

@@ -1,52 +1,31 @@
 #include "bytecode.h"
 #include "value.h"
 #include "vm.h"
+#include "parser.h"
 #include <stdio.h>
 
-int main(void) {
+int main(int argc, char **argv) {
     VM vm;
     vm_init(&vm);
 
-    /* Example: 0..4 loop */
-    Bytecode *bc = bytecode_new();
-    int c0  = bytecode_add_constant(bc, make_int(0));
-    int c1  = bytecode_add_constant(bc, make_int(1));
-    int c5  = bytecode_add_constant(bc, make_int(5));
+    // If a script path is provided, parse and run it
+    if (argc > 1) {
+        const char *path = argv[1];
+        Bytecode *bc = parse_file_to_bytecode(path);
+        if (!bc) {
+            fprintf(stderr, "Failed to compile script: %s\n", path);
+            return 1;
+        }
+        vm_run(&vm, bc);
 
-    // initialize i = 0
-    bytecode_add_instruction(bc, OP_LOAD_CONST, c0);
-    bytecode_add_instruction(bc, OP_STORE_LOCAL, 0);
+        // Print captured output for user scripts
+        vm_print_output(&vm);
+        vm_clear_output(&vm);
 
-    int lbl_start = bc->instr_count;
-
-    // load i
-    bytecode_add_instruction(bc, OP_LOAD_LOCAL, 0);
-    bytecode_add_instruction(bc, OP_PRINT, 0);
-
-    // i = i + 1
-    bytecode_add_instruction(bc, OP_LOAD_LOCAL, 0);
-    bytecode_add_instruction(bc, OP_LOAD_CONST, c1);
-    bytecode_add_instruction(bc, OP_ADD, 0);
-    bytecode_add_instruction(bc, OP_STORE_LOCAL, 0);
-
-    // check i < 5
-    bytecode_add_instruction(bc, OP_LOAD_LOCAL, 0);
-    bytecode_add_instruction(bc, OP_LOAD_CONST, c5);
-    bytecode_add_instruction(bc, OP_LT, 0);
-    int jmp_back = bytecode_add_instruction(bc, OP_JUMP_IF_FALSE, 0);
-    bytecode_add_instruction(bc, OP_JUMP, lbl_start);
-
-    int end_lbl = bc->instr_count;
-    bytecode_set_operand(bc, jmp_back, end_lbl);
-
-    bytecode_add_instruction(bc, OP_HALT, 0);
-
-    vm_run(&vm, bc);
-
-    // flush captured outputs
-    vm_clear_output(&vm);
-
-    bytecode_free(bc);
+        bytecode_free(bc);
+        return 0;
+    }
+    
     return 0;
 }
 

src/parser.c

@@ -0,0 +1,193 @@
+#include "parser.h"
+#include "value.h"
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <ctype.h>
+
+static char *read_file_all(const char *path, size_t *out_len) {
+    FILE *f = fopen(path, "rb");
+    if (!f) return NULL;
+    if (fseek(f, 0, SEEK_END) != 0) { fclose(f); return NULL; }
+    long sz = ftell(f);
+    if (sz < 0) { fclose(f); return NULL; }
+    rewind(f);
+    char *buf = (char*)malloc((size_t)sz + 1);
+    if (!buf) { fclose(f); return NULL; }
+    size_t n = fread(buf, 1, (size_t)sz, f);
+    fclose(f);
+    buf[n] = '\0';
+    if (out_len) *out_len = n;
+    return buf;
+}
+
+static void skip_ws(const char *src, size_t len, size_t *pos) {
+    while (*pos < len) {
+        char c = src[*pos];
+        if (c == ' ' || c == '\t' || c == '\r' || c == '\n') { (*pos)++; continue; }
+        break;
+    }
+}
+
+static void skip_line(const char *src, size_t len, size_t *pos) {
+    while (*pos < len && src[*pos] != '\n') (*pos)++;
+    if (*pos < len && src[*pos] == '\n') (*pos)++;
+}
+
+static void skip_comments(const char *src, size_t len, size_t *pos) {
+    for (;;) {
+        skip_ws(src, len, pos);
+        if (*pos + 1 < len && src[*pos] == '/' && src[*pos + 1] == '/') {
+            *pos += 2;
+            skip_line(src, len, pos);
+            continue;
+        }
+        if (*pos + 1 < len && src[*pos] == '/' && src[*pos + 1] == '*') {
+            *pos += 2;
+            while (*pos + 1 < len && !(src[*pos] == '*' && src[*pos + 1] == '/')) (*pos)++;
+            if (*pos + 1 < len) *pos += 2;
+            continue;
+        }
+        break;
+    }
+}
+
+static int starts_with(const char *src, size_t len, size_t pos, const char *kw) {
+    size_t klen = strlen(kw);
+    if (pos + klen > len) return 0;
+    return strncmp(src + pos, kw, klen) == 0;
+}
+
+static void skip_shebang_if_present(const char *src, size_t len, size_t *pos) {
+    if (*pos == 0 && starts_with(src, len, *pos, "#!")) {
+        skip_line(src, len, pos);
+    }
+}
+
+static void skip_identifier(const char *src, size_t len, size_t *pos) {
+    size_t p = *pos;
+    if (p < len && (isalpha((unsigned char)src[p]) || src[p] == '_')) {
+        p++;
+        while (p < len && (isalnum((unsigned char)src[p]) || src[p] == '_')) p++;
+    }
+    *pos = p;
+}
+
+static int consume_char(const char *src, size_t len, size_t *pos, char expected) {
+    skip_ws(src, len, pos);
+    if (*pos < len && src[*pos] == expected) { (*pos)++; return 1; }
+    return 0;
+}
+
+static char *parse_string_literal_any_quote(const char *src, size_t len, size_t *pos) {
+    skip_ws(src, len, pos);
+    if (*pos >= len) return NULL;
+    char quote = src[*pos];
+    if (quote != '"' && quote != '\'') return NULL;
+    (*pos)++; // skip opening quote
+    size_t cap = 64, out_len = 0;
+    char *out = (char*)malloc(cap);
+    if (!out) return NULL;
+    while (*pos < len) {
+        char c = src[*pos];
+        if (c == quote) { (*pos)++; break; }
+        if (c == '\\') {
+            (*pos)++;
+            if (*pos >= len) break;
+            char e = src[*pos];
+            switch (e) {
+                case 'n': c = '\n'; break;
+                case 'r': c = '\r'; break;
+                case 't': c = '\t'; break;
+                case '\\': c = '\\'; break;
+                case '"': c = '"'; break;
+                case '\'': c = '\''; break;
+                default: c = e; break;
+            }
+        }
+        if (out_len + 1 >= cap) {
+            cap *= 2;
+            char *tmp = (char*)realloc(out, cap);
+            if (!tmp) { free(out); return NULL; }
+            out = tmp;
+        }
+        out[out_len++] = c;
+        (*pos)++;
+    }
+    if (out_len + 1 >= cap) {
+        char *tmp = (char*)realloc(out, cap + 1);
+        if (!tmp) { free(out); return NULL; }
+        out = tmp;
+    }
+    out[out_len] = '\0';
+    return out;
+}
+
+/*
+ * Very small compiler:
+ * - Optionally skips: fun <ident>() { ... } wrapper.
+ * - Emits LOAD_CONST (string) + PRINT for each print("...") encountered.
+ * - Ends with HALT.
+ */
+static Bytecode *compile_minimal(const char *src, size_t len) {
+    Bytecode *bc = bytecode_new();
+    size_t pos = 0;
+
+    skip_shebang_if_present(src, len, &pos);
+
+    // Optionally consume a single function wrapper: fun <ident>() { ... }
+    skip_comments(src, len, &pos);
+    skip_ws(src, len, &pos);
+    if (starts_with(src, len, pos, "fun")) {
+        pos += 3;
+        skip_comments(src, len, &pos);
+        skip_ws(src, len, &pos);
+        skip_identifier(src, len, &pos);  // function name
+        skip_comments(src, len, &pos);
+        skip_ws(src, len, &pos);
+        (void)consume_char(src, len, &pos, '(');
+        (void)consume_char(src, len, &pos, ')');
+        skip_comments(src, len, &pos);
+        skip_ws(src, len, &pos);
+        (void)consume_char(src, len, &pos, '{');  // braces optional; if not present, we continue anyway
+    }
+
+    // Parse statements until EOF or closing brace
+    while (pos < len) {
+        skip_comments(src, len, &pos);
+        skip_ws(src, len, &pos);
+        if (pos < len && src[pos] == '}') { pos++; break; }
+
+        if (starts_with(src, len, pos, "print")) {
+            pos += 5;
+            (void)consume_char(src, len, &pos, '(');
+            char *s = parse_string_literal_any_quote(src, len, &pos);
+            if (s) {
+                int ci = bytecode_add_constant(bc, make_string(s));
+                free(s);
+                bytecode_add_instruction(bc, OP_LOAD_CONST, ci);
+                bytecode_add_instruction(bc, OP_PRINT, 0);
+            }
+            (void)consume_char(src, len, &pos, ')');
+            continue;
+        }
+
+        // Unknown/unsupported token: advance to avoid infinite loop
+        pos++;
+    }
+
+    bytecode_add_instruction(bc, OP_HALT, 0);
+    return bc;
+}
+
+Bytecode *parse_file_to_bytecode(const char *path) {
+    size_t len = 0;
+    char *src = read_file_all(path, &len);
+    if (!src) {
+        fprintf(stderr, "Error: cannot read file: %s\n", path);
+        return NULL;
+    }
+    Bytecode *bc = compile_minimal(src, len);
+    free(src);
+    return bc;
+}

src/parser.h

@@ -0,0 +1,19 @@
+/*
+ * Parse a .fun source file and compile it into entry bytecode.
+ * Minimal support:
+ *  - Optional shebang on the first line.
+ *  - Optional single function wrapper: fun <ident>() { ... }
+ *  - print("...") statements inside function or at top-level.
+ * Produces bytecode that executes all discovered print statements and halts.
+ *
+ * Returns: newly allocated Bytecode*, or NULL on error.
+ */
+
+#ifndef FUN_PARSER_H
+#define FUN_PARSER_H
+
+#include "bytecode.h"
+
+Bytecode *parse_file_to_bytecode(const char *path);
+
+#endif

src/vm.h

@@ -39,13 +39,12 @@ typedef struct {
 // initialize VM (zero state)
 void vm_init(VM *vm);
 
-// run entry Bytecode (pushes first frame)
-void vm_run(VM *vm, Bytecode *entry);
-
 // helper function to clear the output
 void vm_clear_output(VM *vm);
-
+void vm_print_output(VM *vm);
 void vm_free(VM *vm);
+// run entry Bytecode (pushes first frame)
+void vm_run(VM *vm, Bytecode *entry);
 
 static inline int opcode_is_valid(int op) {
     return op >= OP_NOP && op <= OP_SWAP;  // all current opcodes