DEV: AST enum for a shape.

src/ast/mod.rs

@@ -19,7 +19,7 @@ use std::cmp::Eq;
 use std::cmp::Ordering;
 use std::cmp::PartialEq;
 use std::cmp::PartialOrd;
-use std::convert::Into;
+use std::convert::{Into, TryFrom, TryInto};
 use std::fmt;
 use std::hash::Hash;
 use std::hash::Hasher;
@@ -30,6 +30,7 @@ use abortable_parser;
 
 use crate::build::scope::Scope;
 use crate::build::Val;
+use crate::error::BuildError;
 
 pub mod printer;
 pub mod walk;
@@ -218,21 +219,58 @@ macro_rules! make_expr {
 /// This is usually used as the body of a tuple in the UCG AST.
 pub type FieldList = Vec<(Token, Expression)>; // Token is expected to be a symbol
 
-/// Represents a Value in the UCG parsed AST.
-#[derive(Debug, PartialEq, Clone)]
-pub enum Value {
-    // Constant Values
-    Empty(Position),
-    Boolean(PositionedItem<bool>),
-    Int(PositionedItem<i64>),
-    Float(PositionedItem<f64>),
-    Str(PositionedItem<String>),
-    Symbol(PositionedItem<String>),
-    // Complex Values
-    Tuple(PositionedItem<FieldList>),
-    List(ListDef),
+pub type ShapeTuple = Vec<(Token, Shape)>;
+pub type ShapeList = Vec<Shape>;
+
+#[derive(PartialEq, Debug, Clone)]
+pub struct FuncShapeDef {
+    args: Vec<Shape>,
+    ret: Box<Shape>,
 }
 
+#[derive(PartialEq, Debug, Clone)]
+pub struct ModuleShapeDef {
+    items: ShapeTuple,
+    ret: Box<Shape>,
+}
+
+macro_rules! value_enum {
+    ($doc:meta $i:tt, $t:ty, $l:ty, $($extra:tt)*) => {
+        #[$doc]
+        #[derive(PartialEq, Debug, Clone)]
+        pub enum $i {
+            // Simple Values
+            Empty(Position),
+            Boolean(PositionedItem<bool>),
+            Int(PositionedItem<i64>),
+            Float(PositionedItem<f64>),
+            Str(PositionedItem<String>),
+            Symbol(PositionedItem<String>),
+            // Complex Values
+            Tuple(PositionedItem<$t>),
+            List($l),
+            // Extra items
+            $( $extra )*
+        }
+    }
+}
+
+value_enum!(
+    doc="Value types represent the Values that UCG can have."
+    Value,
+    FieldList,
+    ListDef,
+);
+
+value_enum!(
+    doc="Shapes represent the types that UCG values or expressions can have."
+    Shape,
+    ShapeTuple,
+    PositionedItem<ShapeList>,
+    Func(FuncShapeDef),
+    Module(ModuleShapeDef),
+);
+
 impl Value {
     /// Returns the type name of the Value it is called on as a string.
     pub fn type_name(&self) -> String {
@@ -307,6 +345,43 @@ impl Value {
             &Value::List(_)
         )
     }
+
+    fn derive_shape(&self) -> Result<Shape, BuildError> {
+        let shape = match self {
+            Value::Empty(p) => Shape::Empty(p.clone()),
+            Value::Boolean(p) => Shape::Boolean(p.clone()),
+            Value::Int(p) => Shape::Int(p.clone()),
+            Value::Float(p) => Shape::Float(p.clone()),
+            Value::Str(p) => Shape::Str(p.clone()),
+            // Symbols in a shape are placeholder. They allow a form of genericity
+            // in the shape. They can be any type and are only refined down.
+            // by their presence in an expression.
+            Value::Symbol(p) => Shape::Symbol(p.clone()),
+            Value::Tuple(flds) => {
+                let mut field_shapes = Vec::new();
+                for &(ref tok, ref expr) in &flds.val {
+                    field_shapes.push((tok.clone(), expr.try_into()?));
+                }
+                Shape::Tuple(PositionedItem::new(field_shapes, flds.pos.clone()))
+            }
+            Value::List(flds) => {
+                let mut field_shapes = Vec::new();
+                for f in &flds.elems {
+                    field_shapes.push(f.try_into()?);
+                }
+                Shape::List(PositionedItem::new(field_shapes, flds.pos.clone()))
+            }
+        };
+        Ok(shape)
+    }
+}
+
+impl TryFrom<&Value> for Shape {
+    type Error = crate::error::BuildError;
+
+    fn try_from(v: &Value) -> Result<Self, Self::Error> {
+        v.derive_shape()
+    }
 }
 
 /// Represents an expansion of a Macro that is expected to already have been
@@ -769,6 +844,28 @@ impl Expression {
             &Expression::Debug(ref def) => &def.pos,
         }
     }
+
+    fn derive_shape(&self) -> Result<Shape, BuildError> {
+        // FIXME(jwall): Implement this
+        let shape = match self {
+            Expression::Simple(ref v) => v.try_into()?,
+            Expression::Format(def) => {
+                Shape::Str(PositionedItem::new("".to_owned(), def.pos.clone()))
+            }
+            Expression::Not(def) => Shape::Boolean(PositionedItem::new(true, def.pos.clone())),
+            Expression::Grouped(v, _pos) => v.as_ref().try_into()?,
+            _ => Shape::Empty(Position::new(0, 0, 0)),
+        };
+        Ok(shape)
+    }
+}
+
+impl TryFrom<&Expression> for Shape {
+    type Error = crate::error::BuildError;
+
+    fn try_from(e: &Expression) -> Result<Self, Self::Error> {
+        e.derive_shape()
+    }
 }
 
 impl fmt::Display for Expression {
@@ -868,3 +965,6 @@ impl Statement {
         }
     }
 }
+
+#[cfg(test)]
+mod test;

src/ast/test.rs

@@ -0,0 +1,128 @@
+// Copyright 2020 Jeremy Wall
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+use crate::ast::{
+    Expression, FormatArgs, FormatDef, ListDef, NotDef, Position, PositionedItem, Shape, Token,
+    TokenType, Value,
+};
+
+#[test]
+fn derive_shape_values() {
+    let value_cases = vec![
+        (
+            Value::Empty(Position::new(0, 0, 0)),
+            Shape::Empty(Position::new(0, 0, 0)),
+        ),
+        (
+            Value::Boolean(PositionedItem::new(false, Position::new(0, 1, 2))),
+            Shape::Boolean(PositionedItem::new(false, Position::new(0, 1, 2))),
+        ),
+        (
+            Value::Boolean(PositionedItem::new(true, Position::new(0, 1, 2))),
+            Shape::Boolean(PositionedItem::new(true, Position::new(0, 1, 2))),
+        ),
+        (
+            Value::Int(PositionedItem::new(1, Position::new(0, 1, 2))),
+            Shape::Int(PositionedItem::new(1, Position::new(0, 1, 2))),
+        ),
+        (
+            Value::Float(PositionedItem::new(2.0, Position::new(0, 1, 2))),
+            Shape::Float(PositionedItem::new(2.0, Position::new(0, 1, 2))),
+        ),
+        (
+            Value::Str(PositionedItem::new(
+                "foo".to_owned(),
+                Position::new(0, 1, 2),
+            )),
+            Shape::Str(PositionedItem::new(
+                "foo".to_owned(),
+                Position::new(0, 1, 2),
+            )),
+        ),
+        (
+            Value::Tuple(PositionedItem::new(
+                vec![(
+                    Token::new("foo", TokenType::BAREWORD, Position::new(0, 0, 0)),
+                    Expression::Simple(Value::Int(PositionedItem::new(3, Position::new(0, 0, 0)))),
+                )],
+                Position::new(0, 0, 0),
+            )),
+            Shape::Tuple(PositionedItem::new(
+                vec![(
+                    Token::new("foo", TokenType::BAREWORD, Position::new(0, 0, 0)),
+                    Shape::Int(PositionedItem::new(3, Position::new(0, 0, 0))),
+                )],
+                Position::new(0, 0, 0),
+            )),
+        ),
+        (
+            Value::List(ListDef {
+                elems: vec![Expression::Simple(Value::Int(PositionedItem::new(
+                    3,
+                    Position::new(0, 0, 0),
+                )))],
+                pos: Position::new(0, 0, 0),
+            }),
+            Shape::List(PositionedItem::new(
+                vec![Shape::Int(PositionedItem::new(3, Position::new(0, 0, 0)))],
+                Position::new(0, 0, 0),
+            )),
+        ),
+    ];
+
+    for (val, shape) in value_cases {
+        assert_eq!(val.derive_shape().unwrap(), shape);
+    }
+}
+
+#[test]
+fn derive_shape_expressions() {
+    let expr_cases = vec![
+        (
+            Expression::Simple(Value::Int(PositionedItem::new(3, Position::new(0, 0, 0)))),
+            Shape::Int(PositionedItem::new(3, Position::new(0, 0, 0))),
+        ),
+        (
+            Expression::Grouped(
+                Box::new(Expression::Simple(Value::Int(PositionedItem::new(
+                    3,
+                    Position::new(0, 0, 0),
+                )))),
+                Position::new(0, 0, 0),
+            ),
+            Shape::Int(PositionedItem::new(3, Position::new(0, 0, 0))),
+        ),
+        (
+            Expression::Format(FormatDef {
+                template: "".to_owned(),
+                args: FormatArgs::List(Vec::new()),
+                pos: Position::new(0, 0, 0),
+            }),
+            Shape::Str(PositionedItem::new("".to_owned(), Position::new(0, 0, 0))),
+        ),
+        (
+            Expression::Not(NotDef {
+                expr: Box::new(Expression::Simple(Value::Boolean(PositionedItem::new(
+                    true,
+                    Position::new(0, 0, 0),
+                )))),
+                pos: Position::new(1, 0, 0),
+            }),
+            Shape::Boolean(PositionedItem::new(true, Position::new(1, 0, 0))),
+        ),
+    ];
+
+    for (expr, shape) in expr_cases {
+        assert_eq!(expr.derive_shape().unwrap(), shape);
+    }
+}

src/build/opcode/translate.rs

@@ -402,6 +402,8 @@ impl AST {
             Expression::Func(def) => {
                 ops.push(Op::InitList, def.pos.clone());
                 for b in def.argdefs {
+                    // FIXME(jwall): if there is a projection
+                    // then add the projection check here?
                     ops.push(Op::Sym(b.val), b.pos.clone());
                     ops.push(Op::Element, b.pos);
                 }
@@ -460,6 +462,8 @@ impl AST {
                 // Init our module tuple bindings
                 ops.push(Op::InitTuple, def.pos.clone());
                 for (t, e) in argset {
+                    // FIXME(jwall): if there is a projection
+                    // then add the projection check here?
                     ops.push(Op::Sym(t.fragment), t.pos.clone());
                     Self::translate_expr(e, &mut ops, root);
                     ops.push(Op::Field, t.pos);