Change if-expr syntax

use else instead of ->

schala-lang/language/src/eval/test.rs

@@ -96,26 +96,26 @@ fn full_if_matching() {
   let source = r#"
 type Option<T> = Some(T) | None
 let a = Option::None
-if a { is Option::None -> 4, is Option::Some(x) -> x }
+if a { is Option::None then 4, is Option::Some(x) then x }
 "#;
 test_in_fresh_env!(source, "4");
 
 let source = r#"
 type Option<T> = Some(T) | None
 let a = Option::Some(99)
-if a { is Option::None -> 4, is Option::Some(x) -> x }
+if a { is Option::None then 4, is Option::Some(x) then x }
 "#;
 test_in_fresh_env!(source, "99");
 
 let source = r#"
 let a = 10
-if a { is 10 -> "x", is 4 -> "y" }
+if a { is 10 then "x", is 4 then "y" }
 "#;
 test_in_fresh_env!(source, "\"x\"");
 
 let source = r#"
 let a = 10
-if a { is 15 -> "x", is 10 -> "y" }
+if a { is 15 then "x", is 10 then "y" }
 "#;
 test_in_fresh_env!(source, "\"y\"");
 }
@@ -124,7 +124,7 @@ test_in_fresh_env!(source, "\"y\"");
 fn string_pattern() {
   let source = r#"
 let a = "foo"
-if a { is "foo" -> "x", is _ -> "y" }
+if a { is "foo" then "x", is _ then "y" }
 "#;
 test_in_fresh_env!(source, "\"x\"");
 }
@@ -134,8 +134,8 @@ fn boolean_pattern() {
   let source = r#"
 let a = true
 if a { 
-  is true -> "x",
-  is false -> "y"
+  is true then "x",
+  is false then "y"
 }
 "#;
 test_in_fresh_env!(source, "\"x\"");
@@ -145,7 +145,7 @@ test_in_fresh_env!(source, "\"x\"");
 fn boolean_pattern_2() {
   let source = r#"
 let a = false
-if a { is true -> "x", is false -> "y" }
+if a { is true then "x", is false then "y" }
 "#;
 test_in_fresh_env!(source, "\"y\"");
 }
@@ -155,7 +155,7 @@ fn ignore_pattern() {
   let source = r#"
 type Option<T> = Some(T) | None
 if Option::Some(10) {
-  is _ -> "hella"
+  is _ then "hella"
 }
 "#;
 test_in_fresh_env!(source, "\"hella\"");
@@ -165,8 +165,8 @@ test_in_fresh_env!(source, "\"hella\"");
 fn tuple_pattern() {
   let source = r#"
 if (1, 2) {
-  is (1, x) -> x,
-  is _ -> 99
+  is (1, x) then x,
+  is _ then 99
 }
 "#;
 test_in_fresh_env!(source, 2);
@@ -177,8 +177,8 @@ test_in_fresh_env!(source, 2);
 fn tuple_pattern_2() {
   let source = r#"
 if (1, 2) {
-  is (10, x) -> x,
-  is (y, x) -> x + y
+  is (10, x) then x,
+  is (y, x) then x + y
 }
 "#;
 test_in_fresh_env!(source, 3);
@@ -188,8 +188,8 @@ test_in_fresh_env!(source, 3);
 fn tuple_pattern_3() {
   let source = r#"
 if (1, 5) {
-  is (10, x) -> x,
-  is (1, x) -> x
+  is (10, x) then x,
+  is (1, x) then x
 }
 "#;
 test_in_fresh_env!(source, 5);
@@ -199,8 +199,8 @@ test_in_fresh_env!(source, 5);
 fn tuple_pattern_4() {
   let source = r#"
 if (1, 5) {
-  is (10, x) -> x,
-  is (1, x) -> x,
+  is (10, x) then x,
+  is (1, x) then x,
 }
 "#;
 test_in_fresh_env!(source, 5);
@@ -215,21 +215,21 @@ let b = Stuff::Jugs(1, "haha")
 let c = Stuff::Mardok
 
 let x = if a {
-  is Stuff::Mulch(20) -> "x",
-  is _ -> "ERR"
+  is Stuff::Mulch(20) then "x",
+  is _ then "ERR"
 }
 
 let y = if b {
-  is Stuff::Mulch(n) -> "ERR",
-  is Stuff::Jugs(2, _) -> "ERR",
-  is Stuff::Jugs(1, s) -> s,
-  is _ -> "ERR",
+  is Stuff::Mulch(n) then "ERR",
+  is Stuff::Jugs(2, _) then "ERR",
+  is Stuff::Jugs(1, s) then s,
+  is _ then "ERR",
 }
 
 let z = if c {
-  is Stuff::Jugs(_, _) -> "ERR",
-  is Stuff::Mardok -> "NIGH",
-  is _ -> "ERR",
+  is Stuff::Jugs(_, _) then "ERR",
+  is Stuff::Mardok then "NIGH",
+  is _ then "ERR",
 }
 
 (x, y, z)

schala-lang/language/src/parsing.rs

@@ -122,7 +122,7 @@
 //! simple_pattern_match := pattern "then" conditional
 //! else_clause := ε | "else" expr_or_block
 //! guard_block := "{" (guard_arm, ",")* "}"
-//! guard_arm := guard "->" expr_or_block
+//! guard_arm := guard "then" expr_or_block
 //! guard := "is" pattern | (operator)+ precedence_expr
 //! ```
 //!
@@ -894,7 +894,7 @@ impl Parser {
   #[recursive_descent_method]
   fn guard_arm(&mut self) -> ParseResult<GuardArm> {
     let guard = self.guard()?;
-    expect!(self, Operator(ref c) if **c == "->");
+    expect!(self, Keyword(Kw::Then));
     let body = self.expr_or_block()?;
     Ok(GuardArm { guard, body })
   }