More playing around with syntax for if

TODO.md

@@ -1,7 +1,7 @@
 # TODO items
 
 ## General code cleanup
--experiment with storing metadata via ItemIds on AST nodes (cf. https://rust-lang.github.io/rustc-guide/hir.html, https://github.com/rust-lang/rust/blob/master/src/librustc/hir/mod.rs )
+DONE -experiment with storing metadata via ItemIds on AST nodes (cf. https://rust-lang.github.io/rustc-guide/hir.html, https://github.com/rust-lang/rust/blob/master/src/librustc/hir/mod.rs )
 -implement and test open/use statements
 -implement field access
 - standardize on an error type that isn't String
@@ -76,10 +76,43 @@ ex.
 -consult http://gluon-lang.org/book/embedding-api.html
 
 
+## Trying if-syntax again
 
-## Playing around with conditional syntax ideas
+//simple if expr
+if x == 10 then "a" else "z"
+
+//complex if expr
+if x == 10 then {
+  let a = 1
+  let b = 2
+  a + b
+} else {
+  55
+}
+
+// different comparison ops
+if x {
+ == 1 then "a"
+  .isPrime() then "b"
+  else "c"
+}
+
+/* for now disallow `if x == { 1 then ... }`, b/c hard to parse
+
+//simple pattern-matching
+if x is Person("Ivan", age) then age else 0
+
+//match-block equivalent
+if x {
+ is Person("Ivan", _) then "Ivan"
+ is Person(_, age) if age > 13 then "barmitzvah'd"
+ else "foo"
+ }
+
+
+
+## (OLD) Playing around with conditional syntax ideas
 
-- 
 
 - if/match playground