started adding in more complex exps

src/rust/Grammar.re

@@ -29,22 +29,21 @@ module Pat = {
 };
 
 module Stat = {
-    let sort = Sort.of_str("Stat");
-    let stat = nt(sort)
+  let sort = Sort.of_str("Stat");
+  let stat = nt(sort);
 
-    let tbl = [];
-}
+  let tbl = [];
+};
 
 module Item = {
-    let sort = Sort.of_str("Item");
-    let item = nt(sort);
-
-    let tbl = [
-        //function declaration will be our item
-        p(seq([]))
-    ]
-}
+  let sort = Sort.of_str("Item");
+  let item = nt(sort);
 
+  let tbl = [
+    //function declaration will be our item
+    p(seq([])),
+  ];
+};
 
 module Exp = {
   let sort = Sort.of_str("Exp");
@@ -58,43 +57,80 @@ module Exp = {
       t(Int_lit),
       t(Float_lit),
       t(Id_lower),
+      //Parenthetical expression
       seq([c("("), exp, c(")")]),
+      //Arrays
+      seq([c("["), exp, opt(star(exp)), c("]")])
     ]);
 
   let tokc_alt = ss => alt(List.map(c, ss));
   let unary_op = tokc_alt(["&", "&mut", "*", "-", "!"]);
   let mult_ops = tokc_alt(["*", "/", "%"]);
   let add_ops = tokc_alt(["+", "-"]);
-
-  //TODO: ask David; rust says these ops "require parens" for the prec; does this mean that ~a=None?
-  let compare_ops = tokc_alt(["==", "!=", ">", "<", ">=", "<="])
 
-  let assignment_ops = tokc_alt(["=", "+=", "-=", "*=", "/=", "%=", "&=", "|=", "^=", "<<=", ">>="]);
-  let jump_ops = tokc_alt(["return", "break"])
+  //TODO: ask David; rust says these ops "require parens" for the prec; does this mean that ~a=None?
+  let compare_ops = tokc_alt(["==", "!=", ">", "<", ">=", "<="]);
+
+  let assignment_ops =
+    tokc_alt([
+      "=",
+      "+=",
+      "-=",
+      "*=",
+      "/=",
+      "%=",
+      "&=",
+      "|=",
+      "^=",
+      "<<=",
+      ">>=",
+    ]);
+  let jump_ops = tokc_alt(["return", "break"]);
 
-  let tbl = [
-    //question mark op
-    p(seq([c("?"), exp])),
-    //unary operators
-    p(seq([unary_op, exp])),
-    //type cast exp
-    p(~a=L, seq([exp, c("as"), Typ.typ])),
-    //mult
-    p(~a=L, seq([exp, mult_ops, exp])),
-    //add
-    p(~a=L, seq([exp, add_ops, exp])),
-    //comparison ops
-    p(seq([exp, compare_ops, exp])),
-    //bool and
-    p(seq([exp, c("&&"), exp])),
-    //bool or
-    p(seq([exp, c("||"), exp])),
-    //assignment ops
-    p(seq([exp, assignment_ops, exp])),
+  let exp_without_block = [
     //cfg jumps
     p(seq([jump_ops, exp])),
+    //assignment ops
+    p(seq([exp, assignment_ops, exp])),
+    //bool or
+    p(seq([exp, c("||"), exp])),
+    //bool and
+    p(seq([exp, c("&&"), exp])),
+    //comparison ops
+    p(seq([exp, compare_ops, exp])),
+    //add
+    p(~a=L, seq([exp, add_ops, exp])),
+    //mult
+    p(~a=L, seq([exp, mult_ops, exp])),
+    //type cast exp
+    p(~a=L, seq([exp, c("as"), Typ.typ])),
+    //unary operators
+    p(seq([unary_op, exp])),
+    //question mark op
+    p(seq([c("?"), exp])),
     p(operand),
-  ];
+  ]
+
+
+  let block_exp = seq([c("{"), Stat.stat, c("}")])
+
+  let lone_if_exp = seq([c("if"), exp, block_exp])
+  let if_exp = seq([
+     lone_if_exp, opt(
+        alt([
+            seq([c("else"), block_exp]),
+            seq([c("else"), lone_if_exp]),
+            ])
+        )
+  ])
+
+  let exp_with_block = [
+    p(block_exp),
+  ]
+
+  //NOTE: tbl goes from weak -> strong precedence
+  //NOTE: exp without block > exp with block (prec)
+  let tbl = exp_with_block @ exp_without_block
 };
 
 type t = Sort.Map.t(Prec.Table.t(Regex.t));