language: Add closure expressions

blueprintcompiler/gir.py

@@ -189,7 +189,10 @@ class TypeType(BasicType):
 
 
 _BASIC_TYPES = {
+    "bool": BoolType,
     "gboolean": BoolType,
+    "string": StringType,
+    "gchararray": StringType,
     "int": IntType,
     "gint": IntType,
     "gint64": IntType,
@@ -730,6 +733,9 @@ class GirContext:
         return None
 
     def get_type(self, name: str, ns: str) -> T.Optional[GirNode]:
+        if ns is None and name in _BASIC_TYPES:
+            return _BASIC_TYPES[name]()
+
         ns = ns or "Gtk"
 
         if ns not in self.namespaces:

blueprintcompiler/language/__init__.py

@@ -1,5 +1,5 @@
 from .attributes import BaseAttribute, BaseTypedAttribute
-from .expression import CastExpr, IdentExpr, LookupOp, ExprChain
+from .expression import CastExpr, ClosureExpr, Expr, ExprChain, IdentExpr, LookupOp
 from .gobject_object import Object, ObjectContent
 from .gobject_property import Property
 from .gobject_signal import Signal

blueprintcompiler/language/expression.py

@@ -25,13 +25,24 @@ from .types import TypeName
 expr = Pratt()
 
 
-class Expr:
+class Expr(AstNode):
     @property
     def type(self) -> T.Optional[GirType]:
         raise NotImplementedError()
 
+    @property
+    def rhs(self) -> T.Optional["Expr"]:
+        if isinstance(self.parent, ExprChain):
+            children = list(self.parent.children)
+            if children.index(self) + 1 < len(children):
+                return children[children.index(self) + 1]
+            else:
+                return self.parent.rhs
+        else:
+            return None
 
-class ExprChain(Expr, AstNode):
+
+class ExprChain(Expr):
     grammar = expr
 
     @property
@@ -43,14 +54,14 @@ class ExprChain(Expr, AstNode):
         return self.last.type
 
 
-class InfixExpr(Expr, AstNode):
+class InfixExpr(Expr):
     @property
     def lhs(self):
         children = list(self.parent_by_type(ExprChain).children)
         return children[children.index(self) - 1]
 
 
-class IdentExpr(Expr, AstNode):
+class IdentExpr(Expr):
     grammar = UseIdent("ident")
 
     @property
@@ -124,7 +135,45 @@ class CastExpr(InfixExpr):
             )
 
 
+class ClosureExpr(Expr):
+    grammar = [
+        Optional(["$", UseLiteral("extern", True)]),
+        UseIdent("name"),
+        "(",
+        Delimited(ExprChain, ","),
+        ")",
+    ]
+
+    @property
+    def type(self) -> T.Optional[GirType]:
+        if isinstance(self.rhs, CastExpr):
+            return self.rhs.type
+        else:
+            return None
+
+    @property
+    def closure_name(self) -> str:
+        return self.tokens["name"]
+
+    @property
+    def args(self) -> T.List[ExprChain]:
+        return self.children[ExprChain]
+
+    @validate()
+    def cast_to_return_type(self):
+        if not isinstance(self.rhs, CastExpr):
+            raise CompileError(
+                "Closure expression must be cast to the closure's return type"
+            )
+
+    @validate()
+    def builtin_exists(self):
+        if not self.tokens["extern"]:
+            raise CompileError(f"{self.closure_name} is not a builtin function")
+
+
 expr.children = [
+    Prefix(ClosureExpr),
     Prefix(IdentExpr),
     Prefix(["(", ExprChain, ")"]),
     Infix(10, LookupOp),

blueprintcompiler/outputs/xml/__init__.py

@@ -179,7 +179,7 @@ class XmlOutput(OutputFormat):
     def _emit_expression(self, expression: ExprChain, xml: XmlEmitter):
         self._emit_expression_part(expression.children[-1], xml)
 
-    def _emit_expression_part(self, expression, xml: XmlEmitter):
+    def _emit_expression_part(self, expression: Expr, xml: XmlEmitter):
         if isinstance(expression, IdentExpr):
             self._emit_ident_expr(expression, xml)
         elif isinstance(expression, LookupOp):
@@ -188,6 +188,8 @@ class XmlOutput(OutputFormat):
             self._emit_expression(expression, xml)
         elif isinstance(expression, CastExpr):
             self._emit_cast_expr(expression, xml)
+        elif isinstance(expression, ClosureExpr):
+            self._emit_closure_expr(expression, xml)
         else:
             raise CompilerBugError()
 
@@ -204,6 +206,12 @@ class XmlOutput(OutputFormat):
     def _emit_cast_expr(self, expr: CastExpr, xml: XmlEmitter):
         self._emit_expression_part(expr.lhs, xml)
 
+    def _emit_closure_expr(self, expr: ClosureExpr, xml: XmlEmitter):
+        xml.start_tag("closure", function=expr.closure_name, type=expr.type)
+        for arg in expr.args:
+            self._emit_expression_part(arg, xml)
+        xml.end_tag()
+
     def _emit_attribute(
         self, tag: str, attr: str, name: str, value: Value, xml: XmlEmitter
     ):

blueprintcompiler/tokenizer.py

@@ -46,7 +46,7 @@ _tokens = [
     (TokenType.WHITESPACE, r"\s+"),
     (TokenType.COMMENT, r"\/\*[\s\S]*?\*\/"),
     (TokenType.COMMENT, r"\/\/[^\n]*"),
-    (TokenType.OP, r"<<|>>|=>|::|<|>|:=|\.|\|\||\||\+|\-|\*|=|:|/"),
+    (TokenType.OP, r"\$|<<|>>|=>|::|<|>|:=|\.|\|\||\||\+|\-|\*|=|:|/"),
     (TokenType.PUNCTUATION, r"\(|\)|\{|\}|;|\[|\]|\,"),
 ]
 _TOKENS = [(type, re.compile(regex)) for (type, regex) in _tokens]

tests/sample_errors/expr_closure_not_cast.blp

@@ -0,0 +1,5 @@
+using Gtk 4.0;
+
+Label {
+  label: bind $closure();
+}

tests/sample_errors/expr_closure_not_cast.err

@@ -0,0 +1 @@
+4,15,10,Closure expression must be cast to the closure's return type

tests/samples/expr_closure.blp

@@ -0,0 +1,5 @@
+using Gtk 4.0;
+
+Label my-label {
+  label: bind ($my-closure(my-label.margin-bottom)) as (string);
+}

tests/samples/expr_closure.ui

@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<interface>
+  <requires lib="gtk" version="4.0"/>
+  <object class="GtkLabel" id="my-label">
+    <binding name="label">
+      <closure function="my-closure" type="gchararray">
+        <lookup name="margin-bottom" type="GtkLabel">
+          <constant>my-label</constant>
+        </lookup>
+      </closure>
+    </binding>
+  </object>
+</interface>

tests/test_samples.py

@@ -151,6 +151,7 @@ class TestSamples(unittest.TestCase):
         self.assert_sample("combo_box_text")
         self.assert_sample("comments")
         self.assert_sample("enum")
+        self.assert_sample("expr_closure", skip_run=True)  # The closure doesn't exist
         self.assert_sample("expr_lookup")
         self.assert_sample("file_filter")
         self.assert_sample("flags")
@@ -208,6 +209,7 @@ class TestSamples(unittest.TestCase):
         self.assert_sample_error("empty")
         self.assert_sample_error("enum_member_dne")
         self.assert_sample_error("expr_cast_conversion")
+        self.assert_sample_error("expr_closure_not_cast")
         self.assert_sample_error("expr_lookup_dne")
         self.assert_sample_error("expr_lookup_no_properties")
         self.assert_sample_error("filters_in_non_file_filter")