Add type annotations

src/grammar.pest

@@ -3,10 +3,12 @@ file = {
 }
 
 statement  =  { (decl | type_decl | expr) ~ TERMINATE }
-decl       =  { "let" ~ #name = ident ~ #args = (ident)* ~ "=" ~ expr }
+decl       =  { "let" ~ #name = ident ~ #args = (ident)* ~ #type = type_annot? ~ "=" ~ expr }
 block      =  { "{" ~ MLF ~ block_line ~ MLF ~ "}" }
 block_line = _{ expr | (statement ~ MLF)* }
 
+type_annot = { ":" ~ type_expr }
+
 type_decl =  { "type" ~ #name = type_ident ~ "=" ~ type_expr }
 type_expr =  { func | type_term | type_ident }
 type_term = _{ tuple | rec | enum | type_ident }

src/test/statements.rs

@@ -22,6 +22,13 @@ fn it_parses_decl_with_args() {
     }
 }
 
+#[test]
+fn it_parses_decl_with_type() {
+    if let Err(e) = (*TESTER).evaluate_strict("decl-with-type") {
+        panic!("{e}")
+    }
+}
+
 #[test]
 fn it_parses_blocks() {
     parses_to!(parser: SnekParser, input: "let a = { 1 + 1 }", rule: Rule::statement, tokens: [

tests/corpus/statements/decl-with-type.txt

@@ -0,0 +1,66 @@
+Declaration Test
+
+======
+
+let a: Num = 1 + 1
+let add_a x: Num -> Num = x + a
+
+======
+
+(file
+  (statement
+    (decl
+      (ident: "a")
+      (type_annot
+        (type_expr
+          (type_ident
+            (ident: "Num")
+          )
+        )
+      )
+      (expr
+        (infix_expr
+          (literal
+            (integer: "1")
+          )
+          (operator: "+")
+          (expr
+            (literal
+              (integer: "1")
+            )
+          )
+        )
+      )
+    )
+  )
+  (statement
+    (decl
+      (ident: "add_a")
+      (ident: "x")
+      (type_annot
+        (type_expr
+          (func
+            (type_ident
+              (ident: "Num")
+            )
+            (type_expr
+              (type_ident
+                (ident: "Num")
+              )
+            )
+          )
+        )
+      )
+      (expr
+        (infix_expr
+          (ident: "x")
+          (operator: "+")
+          (expr
+            (ident: "a")
+          )
+        )
+      )
+    )
+  )
+  (EOI: "")
+)