case_match_expression split out into its own method

schala-lang/language/src/eval.rs

@@ -7,7 +7,7 @@ use std::io;
 use itertools::Itertools;
 
 use util::ScopeStack;
-use reduced_ast::{ReducedAST, Stmt, Expr, Lit, Func};
+use reduced_ast::{ReducedAST, Stmt, Expr, Lit, Func, Alternative};
 use symbol_table::{SymbolSpec, Symbol, SymbolTable};
 
 pub struct State<'a> {
@@ -193,49 +193,7 @@ impl<'a> State<'a> {
         Conditional { box cond, then_clause, else_clause } => self.conditional(cond, then_clause, else_clause),
         Assign { box val, box expr } => self.assign_expression(val, expr),
         Unit => Ok(Node::Expr(Unit)),
-        CaseMatch { box cond, alternatives } => match self.expression(Node::Expr(cond))? {
+        CaseMatch { box cond, alternatives } => self.case_match_expression(cond, alternatives),
-          Node::PrimObject { name, tag, items } => {
-            for alt in alternatives {
-              if alt.tag.map(|t| t == tag).unwrap_or(true) {
-                let mut inner_state = State {
-                  values: self.values.new_scope(None),
-                  symbol_table_handle: self.symbol_table_handle.clone(),
-                };
-                for (bound_var, val) in alt.bound_vars.iter().zip(items.iter()) {
-                  if let Some(bv) = bound_var.as_ref() {
-                    inner_state.values.insert(bv.clone(), ValueEntry::Binding { constant: true, val: val.clone() });
-                  }
-                }
-
-                if let Some(guard_expr) = alt.guard {
-                  let evaled_guard = inner_state.expression(guard_expr.to_node());
-                  println!("EVALED GUARD: {:?}", evaled_guard);
-                  //continue
-                }
-
-                return inner_state.block(alt.item)
-              }
-            }
-            return Err(format!("PrimObject failed pattern match"));
-          },
-          Node::PrimTuple { .. } => Err(format!("Tuples not implemented")), //TODO make a distinction between not yet implemented and an actual runtime error
-          Node::Expr(e) => {
-            for alt in alternatives {
-              match (alt.guard, alt.tag) {
-                (Some(ref guard_expr), None) => {
-                  match self.expression(guard_expr.clone().to_node())? {
-                    Node::Expr(Expr::Lit(::reduced_ast::Lit::Bool(true))) => 
-                      return self.block(alt.item),
-                    _ => continue,
-                  }
-                },
-                (None, None) => return self.block(alt.item),
-                _ => return Err(format!("Shouldn't match an expr against a pattern"))
-              }
-            }
-            return Err(format!("Expr Failed pattern match"));
-          }
-        },
         UnimplementedSigilValue => Err(format!("Sigil value eval not implemented"))
       }
     }
@@ -393,6 +351,53 @@ impl<'a> State<'a> {
     Ok(Node::Expr(Expr::Unit))
   }
 
+fn case_match_expression(&mut self, cond: Expr, alternatives: Vec<Alternative>) -> EvalResult<Node> {
+  match self.expression(Node::Expr(cond))? {
+    Node::PrimObject { name, tag, items } => {
+      for alt in alternatives {
+        if alt.tag.map(|t| t == tag).unwrap_or(true) {
+          let mut inner_state = State {
+            values: self.values.new_scope(None),
+            symbol_table_handle: self.symbol_table_handle.clone(),
+          };
+          for (bound_var, val) in alt.bound_vars.iter().zip(items.iter()) {
+            if let Some(bv) = bound_var.as_ref() {
+              inner_state.values.insert(bv.clone(), ValueEntry::Binding { constant: true, val: val.clone() });
+            }
+          }
+
+          if let Some(guard_expr) = alt.guard {
+            let evaled_guard = inner_state.expression(guard_expr.to_node());
+            println!("EVALED GUARD: {:?}", evaled_guard);
+            //continue
+          }
+
+          return inner_state.block(alt.item)
+        }
+      }
+      return Err(format!("PrimObject failed pattern match"));
+    },
+    Node::PrimTuple { .. } => Err(format!("Tuples not implemented")), //TODO make a distinction between not yet implemented and an actual runtime error
+    Node::Expr(e) => {
+      for alt in alternatives {
+        match (alt.guard, alt.tag) {
+          (Some(ref guard_expr), None) => {
+            match self.expression(guard_expr.clone().to_node())? {
+              Node::Expr(Expr::Lit(::reduced_ast::Lit::Bool(true))) => 
+                return self.block(alt.item),
+              _ => continue,
+            }
+          },
+          (None, None) => return self.block(alt.item),
+          _ => return Err(format!("Shouldn't match an expr against a pattern"))
+        }
+      }
+      return Err(format!("Expr Failed pattern match"));
+    }
+
+  }
+}
+
   fn value(&mut self, name: Rc<String>) -> EvalResult<Node> {
     use self::ValueEntry::*;
     use self::Func::*;