feat: func type (#3058)

crates/prql_compiler/src/codegen/pl.rs

@@ -61,7 +61,8 @@ impl WriteSource for TyKind {
             .write_between("{", "}", opt),
             Set => Some("set".to_string()),
             Array(elem) => Some(format!("[{}]", elem.write(opt)?)),
-            Function(func) => {
+            Function(None) => Some("func".to_string()),
+            Function(Some(func)) => {
                 let mut r = String::new();
 
                 for t in &func.args {

crates/prql_compiler/src/ir/pl/types.rs

@@ -27,7 +27,7 @@ pub enum TyKind {
     Set,
 
     /// Type of functions with defined params and return types.
-    Function(TyFunc),
+    Function(Option<TyFunc>),
 }
 
 #[derive(Debug, Clone, PartialEq, Serialize, Deserialize, EnumAsInner)]
@@ -146,7 +146,9 @@ impl TyKind {
                 many.iter().any(|(_, any)| any.kind.is_super_type_of(one))
             }
 
-            (TyKind::Function(sup), TyKind::Function(sub)) => {
+            (TyKind::Function(None), TyKind::Function(_)) => true,
+            (TyKind::Function(Some(_)), TyKind::Function(None)) => true,
+            (TyKind::Function(Some(sup)), TyKind::Function(Some(sub))) => {
                 if is_not_super_type_of(sup.return_ty.as_ref(), sub.return_ty.as_ref()) {
                     return false;
                 }

crates/prql_compiler/src/semantic/resolver/mod.rs

@@ -1004,7 +1004,7 @@ fn expr_of_func(func: Func) -> Expr {
 
     Expr {
         ty: Some(Ty {
-            kind: TyKind::Function(ty),
+            kind: TyKind::Function(Some(ty)),
             name: None,
         }),
         ..Expr::new(ExprKind::Func(Box::new(func)))
@@ -1055,6 +1055,12 @@ fn get_stdlib_decl(name: &str) -> Option<ExprKind> {
         "date" => PrimitiveSet::Date,
         "time" => PrimitiveSet::Time,
         "timestamp" => PrimitiveSet::Timestamp,
+        "func" => {
+            return Some(ExprKind::Type(Ty {
+                kind: TyKind::Function(None),
+                name: None,
+            }))
+        }
         _ => return None,
     };
     Some(ExprKind::Type(Ty {

crates/prql_compiler/src/semantic/resolver/snapshots/prql_compiler__semantic__resolver__test__frames_and_names-2.snap

@@ -1,5 +1,5 @@
 ---
-source: prql-compiler/src/semantic/resolver.rs
+source: crates/prql_compiler/src/semantic/resolver/mod.rs
 expression: "resolve_lineage(r#\"\n            from table_1\n            join customers (==customer_no)\n            \"#).unwrap()"
 ---
 columns:
@@ -10,12 +10,12 @@ columns:
       input_name: customers
       except: []
 inputs:
-  - id: 180
+  - id: 182
     name: table_1
     table:
       - default_db
       - table_1
-  - id: 192
+  - id: 194
     name: customers
     table:
       - default_db

crates/prql_compiler/src/semantic/resolver/snapshots/prql_compiler__semantic__resolver__test__frames_and_names-3.snap

@@ -1,32 +1,32 @@
 ---
-source: prql-compiler/src/semantic/resolver.rs
+source: crates/prql_compiler/src/semantic/resolver/mod.rs
 expression: "resolve_lineage(r#\"\n            from e = employees\n            join salaries (==emp_no)\n            group {e.emp_no, e.gender} (\n                aggregate {\n                    emp_salary = average salaries.salary\n                }\n            )\n            \"#).unwrap()"
 ---
 columns:
   - Single:
       name:
         - e
         - emp_no
-      target_id: 219
+      target_id: 221
       target_name: ~
   - Single:
       name:
         - e
         - gender
-      target_id: 220
+      target_id: 222
       target_name: ~
   - Single:
       name:
         - emp_salary
-      target_id: 245
+      target_id: 247
       target_name: ~
 inputs:
-  - id: 180
+  - id: 182
     name: e
     table:
       - default_db
       - employees
-  - id: 214
+  - id: 216
     name: salaries
     table:
       - default_db

crates/prql_compiler/src/semantic/resolver/snapshots/prql_compiler__semantic__resolver__test__frames_and_names.snap

@@ -1,32 +1,32 @@
 ---
-source: prql-compiler/src/semantic/resolver.rs
+source: crates/prql_compiler/src/semantic/resolver/mod.rs
 expression: "resolve_lineage(r#\"\n            from orders\n            select {customer_no, gross, tax, gross - tax}\n            take 20\n            \"#).unwrap()"
 ---
 columns:
   - Single:
       name:
         - orders
         - customer_no
-      target_id: 210
+      target_id: 212
       target_name: ~
   - Single:
       name:
         - orders
         - gross
-      target_id: 211
+      target_id: 213
       target_name: ~
   - Single:
       name:
         - orders
         - tax
-      target_id: 212
+      target_id: 214
       target_name: ~
   - Single:
       name: ~
-      target_id: 214
+      target_id: 216
       target_name: ~
 inputs:
-  - id: 180
+  - id: 182
     name: orders
     table:
       - default_db

crates/prql_compiler/src/semantic/resolver/snapshots/prql_compiler__semantic__resolver__transforms__tests__aggregate_positional_arg-2.snap

@@ -1,5 +1,5 @@
 ---
-source: prql-compiler/src/semantic/transforms.rs
+source: crates/prql_compiler/src/semantic/resolver/transforms.rs
 expression: expr
 ---
 TransformCall:
@@ -21,7 +21,7 @@ TransformCall:
             input_name: c_invoice
             except: []
       inputs:
-        - id: 180
+        - id: 182
           name: c_invoice
           table:
             - default_db
@@ -185,14 +185,14 @@ lineage:
         name:
           - c_invoice
           - issued_at
-        target_id: 203
+        target_id: 205
         target_name: ~
     - Single:
         name: ~
-        target_id: 227
+        target_id: 229
         target_name: ~
   inputs:
-    - id: 180
+    - id: 182
       name: c_invoice
       table:
         - default_db

crates/prql_compiler/src/semantic/resolver/type_resolver.rs

@@ -107,14 +107,14 @@ fn coerce_kind_to_set(resolver: &mut Resolver, expr: ExprKind) -> Result<Ty> {
         // functions
         ExprKind::Func(func) => Ty {
             name: None,
-            kind: TyKind::Function(TyFunc {
+            kind: TyKind::Function(Some(TyFunc {
                 args: func
                     .params
                     .into_iter()
                     .map(|p| p.ty.map(|t| t.into_ty().unwrap()))
                     .collect_vec(),
                 return_ty: Box::new(resolver.fold_type_expr(Some(func.body))?),
-            }),
+            })),
         },
 
         _ => {

crates/prql_compiler/src/semantic/std.prql

@@ -45,6 +45,7 @@ type text
 type date
 type time
 type timestamp
+type `func`
 
 ## Generic array
 # TODO: an array of anything, not just nulls
@@ -133,7 +134,10 @@ let remove = `default_db.bottom`<relation> top<relation> -> <relation> (
   filter (tuple_every (tuple_map _is_null b.*))
   select t.*
 )
-let loop = pipeline top<relation> -> <relation> internal loop
+let loop = func
+  pipeline <transform>
+  top <relation>
+  -> <relation> internal loop
 
 ## Aggregate functions
 # These return either a scalar when used within `aggregate`, or a column when used anywhere else.
@@ -177,11 +181,11 @@ let as = `noresolve.type` column -> <scalar> internal std.as
 let in = pattern value -> <bool> internal in
 
 ## Tuple functions
-let tuple_every = list -> <bool> internal tuple_every
-let tuple_map = fn list -> internal tuple_map
-let tuple_zip = a b -> internal tuple_zip
-let _eq = a -> internal _eq
-let _is_null = a -> _param.a == null
+let tuple_every = func list -> <bool> internal tuple_every
+let tuple_map = func fn <func> list -> internal tuple_map
+let tuple_zip = func a b -> internal tuple_zip
+let _eq = func a -> internal _eq
+let _is_null = func a -> _param.a == null
 
 ## Misc
 let from_text = input<text> `noresolve.format`:csv -> <relation> internal from_text

crates/prql_compiler/src/tests/test.rs

@@ -179,17 +179,16 @@ fn test_append() {
 
     assert_display_snapshot!(compile(r###"
     from employees
-    derive {name, cost = salary}
+    select {name, cost = salary}
     take 3
     append (
         from employees
-        derive {name, cost = salary + bonuses}
+        select {name, cost = salary + bonuses}
         take 10
     )
     "###).unwrap(), @r###"
     WITH table_0 AS (
       SELECT
-        *,
         name,
         salary + bonuses AS cost
       FROM
@@ -202,7 +201,6 @@ fn test_append() {
     FROM
       (
         SELECT
-          *,
           name,
           salary AS cost
         FROM
@@ -3042,7 +3040,7 @@ fn test_closures_and_pipelines() {
     assert_display_snapshot!(compile(
         r###"
     let addthree = a b c -> s"{a} || {b} || {c}"
-    let arg = myarg myfunc -> ( myfunc myarg )
+    let arg = myarg myfunc <func> -> ( myfunc myarg )
 
     from y
     select x = (

crates/prql_parser/src/stmt.rs

@@ -146,7 +146,9 @@ pub fn type_expr() -> impl Parser<Token, Expr, Error = PError> {
 
     let ident = ident().map(ExprKind::Ident);
 
-    let term = literal.or(ident).map_with_span(into_expr);
+    let func = keyword("func").to(ExprKind::Ident(Ident::from_path(vec!["std", "func"])));
+
+    let term = literal.or(ident).or(func).map_with_span(into_expr);
 
     binary_op_parser(term, operator_or())
         .delimited_by(ctrl('<'), ctrl('>'))