From ecb2eb0f87be8a80148a8ef1f44347a3f0159023 Mon Sep 17 00:00:00 2001
From: greg <greg.shuflin@protonmail.com>
Date: Thu, 12 Oct 2017 23:59:52 -0700
Subject: [PATCH] Some more primitive types + binop-checking

---
 src/schala_lang/eval.rs       |  2 +-
 src/schala_lang/type_check.rs | 44 ++++++++++++++++++++++++++++++++---
 2 files changed, 42 insertions(+), 4 deletions(-)

diff --git a/src/schala_lang/eval.rs b/src/schala_lang/eval.rs
index 68987ec..2762032 100644
--- a/src/schala_lang/eval.rs
+++ b/src/schala_lang/eval.rs
@@ -85,7 +85,7 @@ impl ReplState {
     let opstr: &str = &op.0;
     Ok(match (opstr, evaled_lhs, evaled_rhs) {
       ("+", UnsignedInt(l), UnsignedInt(r)) => UnsignedInt(l + r),
-      ("+", Str(s1), Str(s2)) => Str(format!("{}{}", s1, s2)),
+      ("++", Str(s1), Str(s2)) => Str(format!("{}{}", s1, s2)),
       ("-", UnsignedInt(l), UnsignedInt(r)) => UnsignedInt(l - r),
       ("*", UnsignedInt(l), UnsignedInt(r)) => UnsignedInt(l * r),
       ("/", UnsignedInt(l), UnsignedInt(r)) => UnsignedInt(l / r),
diff --git a/src/schala_lang/type_check.rs b/src/schala_lang/type_check.rs
index 05352b6..e7a2979 100644
--- a/src/schala_lang/type_check.rs
+++ b/src/schala_lang/type_check.rs
@@ -1,7 +1,6 @@
 use std::collections::HashMap;
 use std::rc::Rc;
 
-
 //SKOLEMIZATION - how you prevent an unassigned existential type variable from leaking!
 
 use schala_lang::parsing::{AST, Statement, Declaration, Signature, Expression, ExpressionType, Operation, Variant, TypeName};
@@ -329,18 +328,38 @@ impl TypeContext {
 
     Ok(match ex {
       &IntLiteral(_) => TConst(Integer),
+      &FloatLiteral(_) => TConst(Float),
+      &StringLiteral(_) => TConst(StringT),
       &BoolLiteral(_) => TConst(Boolean),
       &Value(ref name) => {
         self.lookup(name)
           .map(|entry| entry.ty)
           .ok_or(format!("Couldn't find {}", name))?
       },
+      &BinExp(ref op, ref lhs, ref rhs) => {
+        let t_lhs = self.infer(lhs)?;
+        match self.infer_op(op)? {
+          TFunc(t1, t2) => {
+            let _ = self.unify(t_lhs, *t1)?;
+            let t_rhs = self.infer(rhs)?;
+            let x = *t2;
+            match x {
+              TFunc(t3, t4) => {
+                let _ = self.unify(t_rhs, *t3)?;
+                *t4
+              },
+              _ => return Err(format!("Not a function type either")),
+            }
+          },
+          _ => return Err(format!("Op {:?} is not a function type", op)),
+        }
+      },
       &Call { ref f, ref arguments } => {
         let tf = self.infer(f)?;
         let targ = self.infer(arguments.get(0).unwrap())?;
         match tf {
           TFunc(box t1, box t2) => {
-            let _ = self.unify(t1, targ);
+            let _ = self.unify(t1, targ)?;
             t2
           },
           _ => return Err(format!("Not a function!")),
@@ -350,11 +369,30 @@ impl TypeContext {
     })
   }
 
-  fn unify(&mut self, t1: Type, t2: Type) -> TypeCheckResult {
+  fn infer_op(&mut self, op: &Operation) -> TypeCheckResult {
     use self::Type::*;
     use self::TypeConst::*;
+    macro_rules! binoptype {
+      ($lhs:expr, $rhs:expr, $out:expr) => { TFunc(Box::new($lhs), Box::new(TFunc(Box::new($rhs), Box::new($out)))) };
+    }
+
+    Ok(match (*op.0).as_ref() {
+      "+" => binoptype!(TConst(Integer), TConst(Integer), TConst(Integer)),
+      "++" => binoptype!(TConst(StringT), TConst(StringT), TConst(StringT)),
+      "-" => binoptype!(TConst(Integer), TConst(Integer), TConst(Integer)),
+      "*" => binoptype!(TConst(Integer), TConst(Integer), TConst(Integer)),
+      "/" => binoptype!(TConst(Integer), TConst(Integer), TConst(Integer)),
+      "%" => binoptype!(TConst(Integer), TConst(Integer), TConst(Integer)),
+      _ => TConst(Bottom)
+    })
+  }
+
+  fn unify(&mut self, t1: Type, t2: Type) -> TypeCheckResult {
+    use self::Type::*;
     use self::TypeVar::*;
 
+    println!("Calling unify with `{:?}` and `{:?}`", t1, t2);
+
     match (&t1, &t2) {
       (&TConst(ref c1), &TConst(ref c2)) if c1 == c2 => Ok(TConst(c1.clone())),
       (&TFunc(ref t1, ref t2), &TFunc(ref t3, ref t4)) => {