update

.gitattributes

@@ -1 +1,5 @@
-*.h linguist-language=c
+# Attributes for GitHub Linguist
+*.h  linguist-language=c
+*.1  linguist-documentation
+*.ac linguist-detectable=false
+*.am linguist-detectable=false

.travis.yml

@@ -0,0 +1,21 @@
+language: c
+
+os:
+  - linux
+  - osx
+
+dist: bionic
+
+compiler:
+  - gcc
+  - clang
+
+branches:
+  only:
+    - master
+
+script:
+  - autoreconf --install
+  - ./configure
+  - make
+  - make check

README.md

@@ -6,56 +6,43 @@ Implementation of Unlambda, an esoteric programming language.
 
 ## Description
 
-The u6a project provides a C implementation of the [Unlambda](http://www.madore.org/~david/programs/unlambda/) programming language, where Unlambda source code can be compiled into bytecode and executed in a virtual machine.
+The u6a project provides a bytecode compiler and a runtime system for the [Unlambda](http://www.madore.org/~david/programs/unlambda/) programming language.
 
-Ideas behind this implementation can be found [here](https://).
+Ideas behind this implementation can be found [here](https://cismon.net/articles/2020/01/30/1580374678582.html).
 
-## Requirements
+## Getting Started
 
-* A POSIX-compliant operating system
-* GNU Autotools
-* GNU Make
-* A C compiler (with C99 support)
-
-## Build
+Building:
 
 ```bash
 # (If not already) Install the required build tools.
 sudo apt install build-essential automake
-
-# Generate configure files.
+# Generate configuration script.
 autoreconf --install
-
-# Run configure script with desired options.
+# Execute configuration script with desired options.
 ./configure --prefix=$HOME
-
-# Compile sources and generate executables.
+# Compile source code and generate executables.
 make
-
 # (Optional) Run tests.
 make check
-
 # (Optional) Install executables and man pages.
 make install
 ```
 
-## Usage
-
-First, compile an Unlambda source file into bytecode.
+Usage:
 
 ```bash
+# Compile an Unlambda source file into bytecode.
 u6ac -o foo.unl.bc foo.unl
-```
-
-Then, execute the bytecode file with the interpreter.
-
-```bash
+# execute the bytecode file.
 u6a foo.unl.bc
 ```
 
 See [**u6ac**(1)](man/u6ac.1) and [**u6a**(1)](man/u6a.1) man pages for details.
 
-## TODOs
+## Future Plans
 
-* `u6adb` - An interactive debugger for Unlambda
+* Interactive debugger: `u6adb`
 * More compile-time optimizations
+* More test cases
+* LLVM backend for `u6ac`

src/codegen.c

@@ -56,8 +56,8 @@ write_bc_header(FILE* restrict output_stream, uint32_t text_len, uint32_t rodata
             .prog_header_size = U6A_BC_PROG_HEADER_SIZE
         },
         .prog = {
-            .text_size        = htonl(text_len * sizeof(uint8_t)),
-            .rodata_size      = htonl(rodata_len * sizeof(struct u6a_token))
+            .text_size        = htonl(text_len * sizeof(struct u6a_vm_ins)),
+            .rodata_size      = htonl(rodata_len * sizeof(uint8_t))
         }
     };
     return 1 == fwrite(&header, sizeof(struct u6a_bc_header), 1, output_stream);
@@ -111,9 +111,9 @@ u6a_codegen(struct u6a_ast_node* ast_arr, uint32_t ast_len) {
         struct u6a_ast_node* rchild = U6A_AN_RIGHT(node, ast_arr);
         if (U6A_AN_FN(lchild) == u6a_tf_app) {
             if (U6A_AN_FN(rchild) == u6a_tf_app) {
-                stack[stack_top++].ins.opcode = u6a_vo_sa;
+                stack[++stack_top].ins.opcode = u6a_vo_sa;
             } else {
-                stack[stack_top++].ins = (struct u6a_vm_ins) {
+                stack[++stack_top].ins = (struct u6a_vm_ins) {
                     .opcode = u6a_vo_app,
                     .operand.fn.second = rchild->value
                 };
@@ -122,12 +122,12 @@ u6a_codegen(struct u6a_ast_node* ast_arr, uint32_t ast_len) {
             if (U6A_AN_FN(rchild) == u6a_tf_app) {
                 if (U6A_AN_FN(lchild) == u6a_tf_d) {
                     text_buffer[text_len].opcode = u6a_vo_del;
-                    stack[stack_top++] = (struct ins_with_offset) {
+                    stack[++stack_top] = (struct ins_with_offset) {
                         .ins.opcode = u6a_vo_la,
                         .offset = text_len++
                     };
                 } else {
-                    stack[stack_top++].ins = (struct u6a_vm_ins) {
+                    stack[++stack_top].ins = (struct u6a_vm_ins) {
                         .opcode = u6a_vo_app,
                         .operand.fn.first = lchild->value
                     };

src/runtime.c

@@ -118,7 +118,7 @@ vm_var_fn_free(struct u6a_vm_var_fn var) {
 bool
 u6a_runtime_info(FILE* restrict input_stream, const char* file_name) {
     struct u6a_bc_header header;
-    if (UNLIKELY(read_bc_header(&header, input_stream))) {
+    if (UNLIKELY(!read_bc_header(&header, input_stream))) {
         u6a_err_invalid_bc_file(err_runtime, file_name);
         return false;
     }
@@ -137,16 +137,18 @@ u6a_runtime_info(FILE* restrict input_stream, const char* file_name) {
 bool
 u6a_runtime_init(struct u6a_runtime_options* options) {
     struct u6a_bc_header header;
-    if (UNLIKELY(read_bc_header(&header, options->istream))) {
+    if (UNLIKELY(!read_bc_header(&header, options->istream))) {
         u6a_err_invalid_bc_file(err_runtime, options->file_name);
         return false;
     }
-    if (UNLIKELY(CHECK_BC_HEADER_VER(header.file))) {
+    if (UNLIKELY(!CHECK_BC_HEADER_VER(header.file))) {
         if (!options->force_exec || header.file.prog_header_size != U6A_BC_FILE_HEADER_SIZE) {
             u6a_err_bad_bc_ver(err_runtime, options->file_name, header.file.ver_major, header.file.ver_minor);
             return false;
         }
     }
+    header.prog.text_size = ntohl(header.prog.text_size);
+    header.prog.rodata_size = ntohl(header.prog.rodata_size);
     text = malloc(header.prog.text_size + sizeof(text_subst));
     if (UNLIKELY(text == NULL)) {
         u6a_err_bad_alloc(err_runtime, header.prog.text_size + sizeof(text_subst));

src/u6ac.c

@@ -73,7 +73,7 @@ process_options(struct arg_options* options, int argc, char** argv) {
     options->optimize_const = false;
     bool syntax_only = false;
     bool verbose = false;
-    char optimize_level;
+    char optimize_level = '1';
     while (true) {
         int result = getopt_long(argc, argv, "o:O::vHV", long_opts, NULL);
         if (result == -1) {
@@ -88,9 +88,6 @@ process_options(struct arg_options* options, int argc, char** argv) {
                 break;
             case 'O':
                 optimize_level = optarg ? optarg[0] : '1';
-                if (optimize_level > '0') {
-                    options->optimize_const = true;
-                }
             case 'p':
                 if (UNLIKELY(options->output_file_prefix)) {
                     break;
@@ -177,6 +174,9 @@ process_options(struct arg_options* options, int argc, char** argv) {
             }
         }
     }
+    if (optimize_level > '0') {
+        options->optimize_const = true;
+    }
     u6a_logging_verbose(verbose);
     return true;
 }