Purity inference

crates/cli/tests/cli_run.rs

@@ -941,6 +941,117 @@ mod cli_run {
         );
     }
 
+    #[test]
+    #[cfg_attr(windows, ignore)]
+    fn effectful_hello() {
+        test_roc_app(
+            "crates/cli/tests/effectful",
+            "hello.roc",
+            &[],
+            &[],
+            &[],
+            indoc!(
+                r#"
+                    I'm an effect 👻
+                    "#
+            ),
+            UseValgrind::No,
+            TestCliCommands::Dev,
+        );
+    }
+
+    #[test]
+    #[cfg_attr(windows, ignore)]
+    fn effectful_form() {
+        test_roc_app(
+            "crates/cli/tests/effectful",
+            "form.roc",
+            &["Agus\n", "Zubiaga\n", "27\n"],
+            &[],
+            &[],
+            indoc!(
+                r#"
+                What's your first name?
+                What's your last name?
+
+                Hi, Agus Zubiaga!
+
+                How old are you?
+
+                Nice! You can vote!
+
+                Bye! 👋
+                "#
+            ),
+            UseValgrind::No,
+            TestCliCommands::Dev,
+        );
+    }
+
+    #[test]
+    #[cfg_attr(windows, ignore)]
+    fn effectful_loops() {
+        test_roc_app(
+            "crates/cli/tests/effectful",
+            "loops.roc",
+            &[],
+            &[],
+            &[],
+            indoc!(
+                r#"
+                    Lu
+                    Marce
+                    Joaquin
+                    Chloé
+                    Mati
+                    Pedro
+                    "#
+            ),
+            UseValgrind::No,
+            TestCliCommands::Dev,
+        );
+    }
+
+    #[test]
+    #[cfg_attr(windows, ignore)]
+    fn effectful_untyped_passed_fx() {
+        test_roc_app(
+            "crates/cli/tests/effectful",
+            "untyped_passed_fx.roc",
+            &[],
+            &[],
+            &[],
+            indoc!(
+                r#"
+                Before hello
+                Hello, World!
+                After hello
+                "#
+            ),
+            UseValgrind::No,
+            TestCliCommands::Dev,
+        );
+    }
+
+    #[test]
+    #[cfg_attr(windows, ignore)]
+    fn effectful_ignore_result() {
+        test_roc_app(
+            "crates/cli/tests/effectful",
+            "ignore_result.roc",
+            &[],
+            &[],
+            &[],
+            indoc!(
+                r#"
+                I asked for input and I ignored it. Deal with it! 😎
+                "#
+            ),
+            UseValgrind::No,
+            TestCliCommands::Dev,
+        );
+    }
+
     #[test]
     #[cfg_attr(windows, ignore)]
     fn transitive_expects() {

crates/cli/tests/effectful/form.roc

@@ -0,0 +1,27 @@
+app [main!] { pf: platform "../../../../examples/cli/effects-platform/main.roc" }
+
+import pf.Effect
+
+main! : {} => {}
+main! = \{} ->
+    first = ask! "What's your first name?"
+    last = ask! "What's your last name?"
+
+    Effect.putLine! "\nHi, $(first) $(last)!\n"
+
+    when Str.toU8 (ask! "How old are you?") is
+        Err InvalidNumStr ->
+            Effect.putLine! "Enter a valid number"
+
+        Ok age if age >= 18 ->
+            Effect.putLine! "\nNice! You can vote!"
+
+        Ok age ->
+            Effect.putLine! "\nYou'll be able to vote in $(Num.toStr (18 - age)) years"
+
+    Effect.putLine! "\nBye! 👋"
+
+ask! : Str => Str
+ask! = \question ->
+    Effect.putLine! question
+    Effect.getLine! {}

crates/cli/tests/effectful/hello.roc

@@ -0,0 +1,7 @@
+app [main!] { pf: platform "../../../../examples/cli/effects-platform/main.roc" }
+
+import pf.Effect
+
+main! : {} => {}
+main! = \{} ->
+    Effect.putLine! "I'm an effect 👻"

crates/cli/tests/effectful/ignore_result.roc

@@ -0,0 +1,8 @@
+app [main!] { pf: platform "../../../../examples/cli/effects-platform/main.roc" }
+
+import pf.Effect
+
+main! : {} => {}
+main! = \{} ->
+    _ = Effect.getLine! {}
+    Effect.putLine! "I asked for input and I ignored it. Deal with it! 😎"

crates/cli/tests/effectful/loops.roc

@@ -0,0 +1,16 @@
+app [main!] { pf: platform "../../../../examples/cli/effects-platform/main.roc" }
+
+import pf.Effect
+
+main! : {} => {}
+main! = \{} ->
+    friends = ["Lu", "Marce", "Joaquin", "Chloé", "Mati", "Pedro"]
+    printAll! friends
+
+printAll! : List Str => {}
+printAll! = \friends ->
+    when friends is
+        [] -> {}
+        [first, .. as remaining] ->
+            Effect.putLine! first
+            printAll! remaining

crates/cli/tests/effectful/untyped_passed_fx.roc

@@ -0,0 +1,12 @@
+app [main!] { pf: platform "../../../../examples/cli/effects-platform/main.roc" }
+
+import pf.Effect
+
+main! : {} => {}
+main! = \{} ->
+    logged! "hello" (\{} -> Effect.putLine! "Hello, World!")
+
+logged! = \name, fx! ->
+    Effect.putLine! "Before $(name)"
+    fx! {}
+    Effect.putLine! "After $(name)"

crates/compiler/builtins/roc/Task.roc

@@ -222,8 +222,8 @@ sequence = \taskList ->
     Task.loop (taskList, List.withCapacity (List.len taskList)) \(tasks, values) ->
         when tasks is
             [task, .. as rest] ->
-                value = task!
-                Task.ok (Step (rest, List.append values value))
+                Task.map task \value ->
+                    Step (rest, List.append values value)
 
             [] ->
                 Task.ok (Done values)

crates/compiler/can/src/annotation.rs

@@ -4,7 +4,9 @@ use crate::scope::{PendingAbilitiesInScope, Scope, SymbolLookup};
 use roc_collections::{ImMap, MutSet, SendMap, VecMap, VecSet};
 use roc_module::ident::{Ident, Lowercase, TagName};
 use roc_module::symbol::Symbol;
-use roc_parse::ast::{AssignedField, ExtractSpaces, Pattern, Tag, TypeAnnotation, TypeHeader};
+use roc_parse::ast::{
+    AssignedField, ExtractSpaces, FunctionArrow, Pattern, Tag, TypeAnnotation, TypeHeader,
+};
 use roc_problem::can::ShadowKind;
 use roc_region::all::{Loc, Region};
 use roc_types::subs::{VarStore, Variable};
@@ -448,7 +450,7 @@ pub fn find_type_def_symbols(
                     stack.push(&t.value);
                 }
             }
-            Function(arguments, result) => {
+            Function(arguments, _arrow, result) => {
                 for t in arguments.iter() {
                     stack.push(&t.value);
                 }
@@ -554,7 +556,7 @@ fn can_annotation_help(
     use roc_parse::ast::TypeAnnotation::*;
 
     match annotation {
-        Function(argument_types, return_type) => {
+        Function(argument_types, arrow, return_type) => {
             let mut args = Vec::new();
 
             for arg in *argument_types {
@@ -589,7 +591,12 @@ fn can_annotation_help(
             introduced_variables.insert_lambda_set(lambda_set);
             let closure = Type::Variable(lambda_set);
 
-            Type::Function(args, Box::new(closure), Box::new(ret))
+            let fx_type = match arrow {
+                FunctionArrow::Pure => Type::Pure,
+                FunctionArrow::Effectful => Type::Effectful,
+            };
+
+            Type::Function(args, Box::new(closure), Box::new(ret), Box::new(fx_type))
         }
         Apply(module_name, ident, type_arguments) => {
             let symbol = match make_apply_symbol(env, region, scope, module_name, ident, references)

crates/compiler/can/src/builtins.rs

@@ -418,6 +418,7 @@ fn defn(
         expr_var: var_store.fresh(),
         pattern_vars: SendMap::default(),
         annotation: None,
+        kind: crate::def::DefKind::Let,
     }
 }
 
@@ -446,6 +447,7 @@ fn defn_help(
         function_type: var_store.fresh(),
         closure_type: var_store.fresh(),
         return_type: ret_var,
+        fx_type: Variable::PURE,
         name: fn_name,
         captured_symbols: Vec::new(),
         recursive: Recursive::NotRecursive,
@@ -546,6 +548,7 @@ fn to_num_checked(symbol: Symbol, var_store: &mut VarStore, lowlevel: LowLevel)
         expr_var: record_var,
         pattern_vars: SendMap::default(),
         annotation: None,
+        kind: crate::def::DefKind::Let,
     };
 
     let body = LetNonRec(Box::new(def), Box::new(no_region(cont)));