Generate effectful hosted functions

crates/compiler/can/src/effect_module.rs

@@ -33,7 +33,7 @@ pub fn build_host_exposed_def(
 
     let def_body = {
         match typ.shallow_structural_dealias() {
-            Type::Function(args, _, _, _) => {
+            Type::Function(args, _, _, fx) if **fx == Type::Pure => {
                 for i in 0..args.len() {
                     let name = format!("closure_arg_{ident}_{i}");
 
@@ -109,6 +109,45 @@ pub fn build_host_exposed_def(
                     loc_body: Box::new(Loc::at_zero(body)),
                 })
             }
+            Type::Function(args, _, _, fx) if **fx == Type::Effectful => {
+                for i in 0..args.len() {
+                    let name = format!("{ident}_arg_{i}");
+
+                    let arg_symbol = {
+                        let ident = name.clone().into();
+                        scope.introduce(ident, Region::zero()).unwrap()
+                    };
+
+                    let arg_var = var_store.fresh();
+
+                    arguments.push((
+                        arg_var,
+                        AnnotatedMark::new(var_store),
+                        Loc::at_zero(Pattern::Identifier(arg_symbol)),
+                    ));
+
+                    linked_symbol_arguments.push((arg_var, Expr::Var(arg_symbol, arg_var)));
+                }
+
+                let foreign_symbol_name = format!("roc_fx_{ident}");
+                let foreign_call = Expr::ForeignCall {
+                    foreign_symbol: foreign_symbol_name.into(),
+                    args: linked_symbol_arguments,
+                    ret_var: var_store.fresh(),
+                };
+
+                Expr::Closure(ClosureData {
+                    function_type: var_store.fresh(),
+                    closure_type: var_store.fresh(),
+                    return_type: var_store.fresh(),
+                    fx_type: var_store.fresh(),
+                    name: symbol,
+                    captured_symbols: std::vec::Vec::new(),
+                    recursive: Recursive::NotRecursive,
+                    arguments,
+                    loc_body: Box::new(Loc::at_zero(foreign_call)),
+                })
+            }
             _ => {
                 // not a function
 

crates/compiler/can/src/lib.rs

@@ -14,6 +14,7 @@ pub mod copy;
 pub mod def;
 mod derive;
 pub mod desugar;
+pub mod effect_module;
 pub mod env;
 pub mod exhaustive;
 pub mod expected;
@@ -25,7 +26,6 @@ pub mod procedure;
 pub mod scope;
 pub mod string;
 pub mod suffixed;
-pub mod task_module;
 pub mod traverse;
 
 pub use derive::DERIVED_REGION;

crates/compiler/can/src/module.rs

@@ -533,7 +533,7 @@ pub fn canonicalize_module_defs<'a>(
                                 aliases: Default::default(),
                             };
 
-                            let hosted_def = crate::task_module::build_host_exposed_def(
+                            let hosted_def = crate::effect_module::build_host_exposed_def(
                                 &mut scope, *symbol, &ident, var_store, annotation,
                             );
 
@@ -586,7 +586,7 @@ pub fn canonicalize_module_defs<'a>(
                                 aliases: Default::default(),
                             };
 
-                            let hosted_def = crate::task_module::build_host_exposed_def(
+                            let hosted_def = crate::effect_module::build_host_exposed_def(
                                 &mut scope, *symbol, &ident, var_store, annotation,
                             );
 

examples/cli/effects-platform/Effect.roc

@@ -0,0 +1,7 @@
+hosted Effect
+    exposes [putLine, getLine]
+    imports []
+
+putLine : Str => {}
+
+getLine : {} => Str

examples/cli/effects-platform/PlatformTasks.roc

@@ -1,7 +0,0 @@
-hosted PlatformTasks
-    exposes [putLine, getLine]
-    imports []
-
-putLine : Str -> Task {} *
-
-getLine : Task Str *

examples/cli/effects-platform/host.zig

@@ -12,9 +12,6 @@ const Allocator = mem.Allocator;
 
 extern fn roc__mainForHost_1_exposed_generic([*]u8) void;
 extern fn roc__mainForHost_1_exposed_size() i64;
-extern fn roc__mainForHost_0_caller(*const u8, [*]u8, [*]u8) void;
-extern fn roc__mainForHost_0_size() i64;
-extern fn roc__mainForHost_0_result_size() i64;
 
 const Align = 2 * @alignOf(usize);
 extern fn malloc(size: usize) callconv(.C) ?*align(Align) anyopaque;
@@ -127,8 +124,6 @@ pub export fn main() u8 {
 
     roc__mainForHost_1_exposed_generic(output);
 
-    call_the_closure(output);
-
     const nanos = timer.read();
     const seconds = (@as(f64, @floatFromInt(nanos)) / 1_000_000_000.0);
 
@@ -141,35 +136,6 @@ fn to_seconds(tms: std.os.timespec) f64 {
     return @as(f64, @floatFromInt(tms.tv_sec)) + (@as(f64, @floatFromInt(tms.tv_nsec)) / 1_000_000_000.0);
 }
 
-fn call_the_closure(closure_data_pointer: [*]u8) void {
-    const allocator = std.heap.page_allocator;
-
-    const size = roc__mainForHost_0_result_size();
-
-    if (size == 0) {
-        // the function call returns an empty record
-        // allocating 0 bytes causes issues because the allocator will return a NULL pointer
-        // So it's special-cased
-        const flags: u8 = 0;
-        var result: [1]u8 = .{0};
-        roc__mainForHost_0_caller(&flags, closure_data_pointer, &result);
-
-        return;
-    }
-
-    const raw_output = allocator.alignedAlloc(u8, @alignOf(u64), @as(usize, @intCast(size))) catch unreachable;
-    var output = @as([*]u8, @ptrCast(raw_output));
-
-    defer {
-        allocator.free(raw_output);
-    }
-
-    const flags: u8 = 0;
-    roc__mainForHost_0_caller(&flags, closure_data_pointer, output);
-
-    return;
-}
-
 pub export fn roc_fx_getLine() str.RocStr {
     return roc_fx_getLine_help() catch return str.RocStr.empty();
 }

examples/cli/effects-platform/main.roc

@@ -1,9 +1,9 @@
 platform "effects"
-    requires {} { main : Task {} [] }
+    requires {} { main : {} => {} }
     exposes []
     packages {}
     imports []
     provides [mainForHost]
 
-mainForHost : Task {} []
-mainForHost = main
+mainForHost : {} => {}
+mainForHost = \{} -> main {}

examples/cli/effects.roc

@@ -1,11 +1,9 @@
 app [main] { pf: platform "effects-platform/main.roc" }
 
-import pf.PlatformTasks
+import pf.Effect
 
-main : Task {} []
-main =
-    line = PlatformTasks.getLine!
-    PlatformTasks.putLine! "You entered: $(line)"
-    PlatformTasks.putLine! "It is known"
-
-    Task.ok {}
+main : {} => {}
+main = \{} ->
+    line = Effect.getLine {}
+    _ = Effect.putLine "You entered: $(line)"
+    Effect.putLine "It is known"