Add examples/cli

examples/.gitignore

@@ -4,4 +4,3 @@ app
 libhost.a
 roc_app.ll
 roc_app.bc
-effect-example

examples/cli/.gitignore

@@ -0,0 +1 @@
+cli-example

examples/cli/Main.roc

@@ -0,0 +1,8 @@
+app "cli-example"
+    packages { base: "platform" }
+    imports [ fx.Effect ]
+    provides [ main ] to base
+
+main : Effect.Effect {}
+main =
+    Effect.after Effect.getLine \lineThisThing -> Effect.putLine lineThisThing

examples/cli/platform/Cargo.lock

@@ -0,0 +1,21 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "host"
+version = "0.1.0"
+dependencies = [
+ "libc",
+ "roc_std",
+]
+
+[[package]]
+name = "libc"
+version = "0.2.92"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "56d855069fafbb9b344c0f962150cd2c1187975cb1c22c1522c240d8c4986714"
+
+[[package]]
+name = "roc_std"
+version = "0.1.0"

examples/cli/platform/Cargo.toml

@@ -0,0 +1,15 @@
+[package]
+name = "host"
+version = "0.1.0"
+authors = ["The Roc Contributors"]
+license = "UPL-1.0"
+edition = "2018"
+
+[lib]
+crate-type = ["staticlib"]
+
+[dependencies]
+roc_std = { path = "../../../roc_std" }
+libc = "0.2"
+
+[workspace]

examples/cli/platform/Package-Config.roc

@@ -0,0 +1,15 @@
+platform examples/cli
+    requires {} { main : Effect {} }
+    exposes []
+    packages {}
+    imports [ fx.Effect ]
+    provides [ mainForHost ]
+    effects fx.Effect
+        {
+            putLine : Str -> Effect {},
+            getLine : Effect Str
+        }
+
+
+mainForHost : Effect.Effect {} as Fx
+mainForHost = main

examples/cli/platform/Stdin.roc

@@ -0,0 +1,17 @@
+interface Stdin
+    exposes [ getInt ]
+    imports [ fx.Effect, Task ]
+
+
+getInt : Task.Task I64 []
+getInt =
+    Effect.after Effect.getInt \{ isError, value, errorCode } ->
+        when isError is
+            True ->
+                when errorCode is
+                    # A -> Task.fail InvalidCharacter
+                    # B -> Task.fail IOError
+                    _ -> Task.succeed -1
+
+            False ->
+                Task.succeed value

examples/cli/platform/Stdout.roc

@@ -0,0 +1,9 @@
+interface Stdout
+    exposes [ putLine, putInt ]
+    imports [ fx.Effect, Task ]
+
+putLine : Str -> Task {} *
+putLine = \line -> Effect.map (Effect.putLine line) (\_ -> Ok {})
+
+putInt : I64 -> Task {} *
+putInt = \line -> Effect.map (Effect.putInt line) (\_ -> Ok {})

examples/cli/platform/Task.roc

@@ -0,0 +1,30 @@
+interface Task
+    exposes [ Task, succeed, fail, after, map ]
+    imports [ fx.Effect ]
+
+
+Task ok err : Effect.Effect (Result ok err)
+
+
+succeed : val -> Task val *
+succeed = \val ->
+    Effect.always (Ok val)
+
+
+fail : err -> Task * err
+fail = \val ->
+    Effect.always (Err val)
+
+after : Task a err, (a -> Task b err) -> Task b err
+after = \effect, transform ->
+    Effect.after effect \result ->
+        when result is
+            Ok a -> transform a
+            Err err -> Task.fail err
+
+map : Task a err, (a -> b) -> Task b err
+map = \effect, transform ->
+    Effect.map effect \result ->
+        when result is
+            Ok a -> Ok (transform a)
+            Err err -> Err err

examples/cli/platform/host.c

@@ -0,0 +1,7 @@
+#include <stdio.h>
+
+extern int rust_main();
+
+int main() {
+  return rust_main();
+}

examples/cli/platform/src/lib.rs

@@ -0,0 +1,132 @@
+#![allow(non_snake_case)]
+
+use core::alloc::Layout;
+use core::ffi::c_void;
+use core::mem::MaybeUninit;
+use roc_std::{RocCallResult, RocStr};
+use std::ffi::CStr;
+use std::os::raw::c_char;
+
+extern "C" {
+    #[link_name = "roc__mainForHost_1_exposed"]
+    fn roc_main(output: *mut u8) -> ();
+
+    #[link_name = "roc__mainForHost_size"]
+    fn roc_main_size() -> i64;
+
+    #[link_name = "roc__mainForHost_1_Fx_caller"]
+    fn call_Fx(flags: *const u8, closure_data: *const u8, output: *mut u8) -> ();
+
+    #[allow(dead_code)]
+    #[link_name = "roc__mainForHost_1_Fx_size"]
+    fn size_Fx() -> i64;
+
+    #[link_name = "roc__mainForHost_1_Fx_result_size"]
+    fn size_Fx_result() -> i64;
+}
+
+#[no_mangle]
+pub unsafe fn roc_alloc(size: usize, _alignment: u32) -> *mut c_void {
+    return libc::malloc(size);
+}
+
+#[no_mangle]
+pub unsafe fn roc_realloc(
+    c_ptr: *mut c_void,
+    new_size: usize,
+    _old_size: usize,
+    _alignment: u32,
+) -> *mut c_void {
+    return libc::realloc(c_ptr, new_size);
+}
+
+#[no_mangle]
+pub unsafe fn roc_dealloc(c_ptr: *mut c_void, _alignment: u32) {
+    return libc::free(c_ptr);
+}
+
+#[no_mangle]
+pub unsafe fn roc_panic(c_ptr: *mut c_void, tag_id: u32) {
+    match tag_id {
+        0 => {
+            let slice = CStr::from_ptr(c_ptr as *const c_char);
+            let string = slice.to_str().unwrap();
+            eprintln!("Roc hit a panic: {}", string);
+            std::process::exit(1);
+        }
+        _ => todo!(),
+    }
+}
+
+#[no_mangle]
+pub fn rust_main() -> isize {
+    let size = unsafe { roc_main_size() } as usize;
+    let layout = Layout::array::<u8>(size).unwrap();
+
+    unsafe {
+        // TODO allocate on the stack if it's under a certain size
+        let buffer = std::alloc::alloc(layout);
+
+        roc_main(buffer);
+
+        let output = buffer as *mut RocCallResult<()>;
+
+        match (&*output).into() {
+            Ok(()) => {
+                let closure_data_ptr = buffer.offset(8);
+                let result = call_the_closure(closure_data_ptr as *const u8);
+
+                std::alloc::dealloc(buffer, layout);
+
+                result
+            }
+            Err(msg) => {
+                std::alloc::dealloc(buffer, layout);
+
+                panic!("Roc failed with message: {}", msg);
+            }
+        }
+    };
+
+    // Exit code
+    0
+}
+
+unsafe fn call_the_closure(closure_data_ptr: *const u8) -> i64 {
+    let size = size_Fx_result() as usize;
+    let layout = Layout::array::<u8>(size).unwrap();
+    let buffer = std::alloc::alloc(layout) as *mut u8;
+
+    call_Fx(
+        // This flags pointer will never get dereferenced
+        MaybeUninit::uninit().as_ptr(),
+        closure_data_ptr as *const u8,
+        buffer as *mut u8,
+    );
+
+    let output = &*(buffer as *mut RocCallResult<()>);
+
+    match output.into() {
+        Ok(_) => 0,
+        Err(e) => panic!("failed with {}", e),
+    }
+}
+
+#[no_mangle]
+pub fn roc_fx_getLine() -> RocStr {
+    use std::io::{self, BufRead};
+
+    let stdin = io::stdin();
+    let line1 = stdin.lock().lines().next().unwrap().unwrap();
+
+    RocStr::from_slice(line1.as_bytes())
+}
+
+#[no_mangle]
+pub fn roc_fx_putLine(line: RocStr) -> () {
+    let bytes = line.as_slice();
+    let string = unsafe { std::str::from_utf8_unchecked(bytes) };
+    println!("{}", string);
+
+    ()
+}