From 421a5160fd38248a4d5a337741586f48b6f255d6 Mon Sep 17 00:00:00 2001
From: Andrew Segavac <andrew@eunomia.io>
Date: Sat, 12 Jun 2021 10:59:58 -0600
Subject: [PATCH] added struct literals

---
 boring/parse.py         | 22 +++++++++++++++++++++-
 boring/type_checking.py | 20 ++++++++++++++++++++
 examples/math/main.bl   |  6 ++++++
 notes.txt               |  2 +-
 4 files changed, 48 insertions(+), 2 deletions(-)

diff --git a/boring/parse.py b/boring/parse.py
index 96f41ee..12673e9 100644
--- a/boring/parse.py
+++ b/boring/parse.py
@@ -68,6 +68,12 @@ class LiteralFloat:
     value: float
     type: TypeUsage
 
+@dataclass
+class LiteralStruct:
+    name: str
+    fields: Dict[str, "Expression"]
+    type: TypeUsage
+
 
 @dataclass
 class FunctionCall:
@@ -101,6 +107,7 @@ class Expression:
     expression: Union[
         LiteralInt,
         LiteralFloat,
+        LiteralStruct,
         FunctionCall,
         "Block",
         ReturnStatement,
@@ -174,9 +181,12 @@ boring_grammar = r"""
     mult : "*"
     div : "/"
 
+    identifier : CNAME
     literal_float : SIGNED_FLOAT
     literal_int : SIGNED_INT
-    identifier : CNAME
+
+    literal_struct_field : identifier ":" expression
+    literal_struct : identifier "{" (literal_struct_field ",")* "}"
 
     function_call : expression "(" [expression ("," expression)*] ")"
 
@@ -199,6 +209,7 @@ boring_grammar = r"""
 
     term : literal_int
          | literal_float
+         | literal_struct
          | variable_usage
          | function_call
          | "(" expression ")"
@@ -280,6 +291,15 @@ class TreeToBoring(Transformer):
         (f,) = f
         return LiteralFloat(value=float(f), type=UnknownTypeUsage())
 
+    def literal_struct_field(self, lsf):
+        (name, expression) = lsf
+        return name, expression
+
+    def literal_struct(self, literal_struct) -> LiteralStruct:
+        name = literal_struct[0]
+        fields = {key: value for (key, value) in literal_struct[1:]}
+        return LiteralStruct(name=name, fields=fields, type=DataTypeUsage(name=name))
+
     def identifier(self, i) -> str:
         (i,) = i
         return str(i)
diff --git a/boring/type_checking.py b/boring/type_checking.py
index ce2f1d1..70c6dcf 100644
--- a/boring/type_checking.py
+++ b/boring/type_checking.py
@@ -224,6 +224,11 @@ class TypeChecker:
             if unify(ctx, subexpression, expression):
                 changed = True
             return changed
+        if isinstance(subexpression, parse.LiteralStruct):
+            changed = self.with_literal_struct(ctx, subexpression)
+            if unify(ctx, subexpression, expression):
+                changed = True
+            return changed
         if isinstance(subexpression, parse.FunctionCall):
             changed = self.with_function_call(ctx, subexpression)
             if unify(ctx, subexpression, expression):
@@ -315,3 +320,18 @@ class TypeChecker:
             assert isinstance(literal_int.type, parse.DataTypeUsage)
             assert literal_int.type.name in ints, f"{literal_int.type}"
         return False
+
+    def with_literal_struct(self, ctx: Context, literal_struct: parse.LiteralStruct) -> bool:
+        assert literal_struct.name in ctx.environment
+        struct_declaration = ctx.environment[literal_struct.name]
+        assert isinstance(struct_declaration, parse.StructTypeDeclaration)
+        changed = False
+        for name, field_type in struct_declaration.fields.items():
+            assert name in literal_struct.fields
+            if self.with_expression(ctx, literal_struct.fields[name]):
+                changed = True
+            result_type, field_changed = type_compare(ctx, field_type, literal_struct.fields[name].type)
+            if field_changed:
+                literal_struct.fields[name].type = result_type
+                changed = True
+        return changed
diff --git a/examples/math/main.bl b/examples/math/main.bl
index 294f0fa..760d008 100644
--- a/examples/math/main.bl
+++ b/examples/math/main.bl
@@ -28,6 +28,12 @@ fn unit_function() {
   let a: I32 = 4;
 }
 
+fn returns_user(): User {
+    return User{
+        id: 4,
+    };
+}
+
 fn main(): I32 {
     add(4, subtract(5, 2))
 }
diff --git a/notes.txt b/notes.txt
index e46db68..35577a6 100644
--- a/notes.txt
+++ b/notes.txt
@@ -39,7 +39,7 @@ TODO:
 * ~Normal assignment~
 * Structs
   * ~Define~
-  * Literal
+  * ~Literal~
   * Getter
   * Setter
 * Generics