More tuple-matching

Also discovered parser bug

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, Alternative};
+use reduced_ast::{BoundVars, ReducedAST, Stmt, Expr, Lit, Func, Alternative, Subpattern};
 use symbol_table::{SymbolSpec, Symbol, SymbolTable};
 
 pub struct State<'a> {
@@ -21,7 +21,6 @@ macro_rules! builtin_binding {
   }
 }
 
-//TODO add a more concise way of getting a new frame
 impl<'a> State<'a> {
   pub fn new(symbol_table_handle: Rc<RefCell<SymbolTable>>) -> State<'a> {
     let mut values = ScopeStack::new(Some(format!("global")));
@@ -34,6 +33,19 @@ impl<'a> State<'a> {
   pub fn debug_print(&self) -> String {
     format!("Values: {:?}", self.values)
   }
+
+  fn new_frame(&'a self, items: &'a Vec<Node>, bound_vars: &BoundVars) -> State<'a> {
+    let mut inner_state = State {
+      values: self.values.new_scope(None),
+      symbol_table_handle: self.symbol_table_handle.clone(),
+    };
+    for (bound_var, val) in 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() });
+      }
+    }
+    inner_state
+  }
 }
 
 #[derive(Debug, Clone)]
@@ -391,19 +403,27 @@ impl<'a> State<'a> {
         }
       }
 
+      fn all_subpatterns_pass(state: &mut State, subpatterns: &Vec<Option<Subpattern>>, items: &Vec<Node>) -> EvalResult<bool> {
+        for (maybe_subp, cond) in subpatterns.iter().zip(items.iter()) {
+          if let Some(subp) = maybe_subp {
+            if let Some(ref guard) = subp.guard {
+              let guard_expr = match &cond {
+                Node::Expr(ref e) => guard.clone().replace_conditional_target_sigil(e),
+                _ => guard.clone()
+              };
+              if !state.expression(guard_expr.to_node())?.is_true() {
+                return Ok(false);
+              }
+            }
+          }
+        }
+        Ok(true)
+      }
+
       match cond {
         Node::PrimObject { ref tag, ref items, .. } => {
           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() });
-              }
-            }
-
+            let mut inner_state = self.new_frame(items, &alt.bound_vars);
             return inner_state.block(alt.item)
           }
         },
@@ -412,32 +432,8 @@ impl<'a> State<'a> {
             return Err(format!("Subpattern length isn't correct"));
           }
 
-          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() });
-            }
-          }
-
-          let mut passes = true;
-          for (maybe_subp, cond) in alt.subpatterns.iter().zip(items.iter()) {
-            if let Some(subp) = maybe_subp {
-              if let Some(ref guard) = subp.guard {
-                let guard_expr = match &cond {
-                  Node::Expr(ref e) => guard.clone().replace_conditional_target_sigil(e),
-                  _ => guard.clone()
-                };
-                if !inner_state.expression(guard_expr.to_node())?.is_true() {
-                  passes = false;
-                  break;
-                }
-              }
-            }
-          }
-          if !passes {
+          let mut inner_state = self.new_frame(items, &alt.bound_vars);
+          if !all_subpatterns_pass(&mut inner_state, &alt.subpatterns, items)? {
             continue;
           }
           return inner_state.block(alt.item)
@@ -644,4 +640,49 @@ if Some(10) {
 "#;
     test_in_fresh_env!(source, "\"hella\"");
   }
+
+  #[test]
+  fn tuple_pattern() {
+    let source = r#"
+if (1, 2) {
+  is (1, x) -> x,
+  is _ -> 99
+}
+"#;
+    test_in_fresh_env!(source, 2);
+  }
+
+
+  #[test]
+  fn tuple_pattern_2() {
+    let source = r#"
+if (1, 2) {
+  is (10, x) -> x,
+  is (y, x) -> x + y
+}
+"#;
+    test_in_fresh_env!(source, 3);
+  }
+
+  #[test]
+  fn tuple_pattern_3() {
+    let source = r#"
+if (1, 5) {
+  is (10, x) -> x,
+  is (1, x) -> x
+}
+"#;
+    test_in_fresh_env!(source, 5);
+  }
+
+  #[test]
+  fn need_to_fix_parser_to_make_work() {
+    let source = r#"
+if (1, 5) {
+  is (10, x) -> x,
+  is (1, x) -> x,
+}
+"#;
+    test_in_fresh_env!(source, 5);
+  }
 }

schala-lang/language/src/reduced_ast.rs

@@ -56,12 +56,14 @@ pub enum Expr {
   UnimplementedSigilValue
 }
 
+pub type BoundVars = Vec<Option<Rc<String>>>; //remember that order matters here
+
 #[derive(Debug, Clone)]
 pub struct Alternative {
   pub tag: Option<usize>,
   pub subpatterns: Vec<Option<Subpattern>>,
   pub guard: Option<Expr>,
-  pub bound_vars: Vec<Option<Rc<String>>>, //remember that order matters here
+  pub bound_vars: BoundVars,
   pub item: Vec<Stmt>,
 }
 
@@ -69,7 +71,7 @@ pub struct Alternative {
 pub struct Subpattern {
   pub tag: Option<usize>,
   pub subpatterns: Vec<Option<Subpattern>>,
-  pub bound_vars: Vec<Option<Rc<String>>>,
+  pub bound_vars: BoundVars,
   pub guard: Option<Expr>,
 }