Add a lot of new stuff to the compile mod

* compile::sym is now compile::name
* add basic block structure
* add visitor pattern
* some other minor things (e.g. syn::ast::prelude)

Signed-off-by: Alek Ratzloff <alekratz@gmail.com>

src/compile/block.rs

@@ -0,0 +1,6 @@
+use crate::compile::ir::Body;
+
+// basic block
+pub enum Block {
+    Body(Body),
+}

src/compile/error.rs

@@ -0,0 +1,9 @@
+use snafu::Snafu;
+
+#[derive(Debug, Snafu)]
+pub enum Error {
+    //#[snafu(display("illegal attr key"))]
+
+}
+
+pub type Result<T, E = Error> = std::result::Result<T, E>;

src/compile/ir.rs

@@ -0,0 +1,59 @@
+use crate::{
+    compile::Ctx,
+    obj::Sym,
+    syn::{ast, span::*},
+};
+
+pub type Body = Vec<Stmt>;
+
+#[derive(Debug, Clone)]
+pub enum Stmt {
+    Eval(Expr),
+    Assign(Lhs, Expr),
+}
+
+#[derive(Debug, Clone)]
+pub enum Lhs {
+    Sym(Sym),
+    Complex(Expr),
+}
+
+#[derive(Debug, Clone)]
+pub enum Expr {
+    Call(Box<Expr>, Vec<Expr>),
+    Base(BaseExpr),
+}
+
+#[derive(Debug, Clone)]
+pub enum BaseExprKind {
+    Num(i64),
+    Str(String),
+    Sym(Sym),
+    Ident(String),
+}
+
+#[derive(Debug, Clone)]
+pub struct BaseExpr {
+    pub kind: BaseExprKind,
+    pub span: Span,
+}
+
+// FromAst and IntoAst are just so we can use .into_ast(ctx, text)
+// some impls may not need ctx &mut ref - but probably needed for symbol resolution
+
+pub trait FromAst<A> {
+    fn from_ast(other: A, ctx: &mut Ctx, text: &str) -> Self;
+}
+
+pub trait IntoIr<I> {
+    fn into_ir(self, ctx: &mut Ctx, text: &str) -> I;
+}
+
+impl<A, I> IntoIr<I> for A
+where
+    I: FromAst<A>,
+{
+    fn into_ir(self, ctx: &mut Ctx, text: &str) -> I {
+        FromAst::from_ast(self, ctx, text)
+    }
+}

src/compile/mod.rs

@@ -1,30 +1,41 @@
-pub mod sym;
+pub mod block;
+pub mod error;
+pub mod ir;
+pub mod name;
+pub mod visit;
 
 use crate::{
     syn::ast::Stmt,
-    compile::sym::SymStack,
+    compile::name::NameStack,
 };
 
-pub trait Pass {
-    type Out;
-    fn pass(&self, ctx: &mut Ctx) -> Self::Out;
-}
-
 // * Desugar
 // * Collect names as symbols
 // * Create basic blocks
 
-pub struct Ctx {
-    sym_stack: SymStack,
+pub struct Ctx<'t> {
+    text: &'t str,
+    name_stack: NameStack,
 }
 
-impl Ctx {
-    pub fn sym_stack(&self) -> &SymStack {
-        &self.sym_stack
+impl<'t> Ctx<'t> {
+    pub fn new(text: &'t str) -> Self {
+        Ctx {
+            text,
+            name_stack: NameStack::new(),
+        }
     }
 
-    pub fn sym_stack_mut(&mut self) -> &mut SymStack {
-        &mut self.sym_stack
+    pub fn text(&self) -> &'t str {
+        self.text
+    }
+
+    pub fn name_stack(&self) -> &NameStack {
+        &self.name_stack
+    }
+
+    pub fn name_stack_mut(&mut self) -> &mut NameStack {
+        &mut self.name_stack
     }
 }
 

src/compile/name.rs

@@ -0,0 +1,161 @@
+use crate::{
+    compile::{visit::*, Ctx},
+    syn::{ast::prelude::*, op::BinOp, span::*},
+};
+use std::collections::HashMap;
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]
+pub struct NameId(usize);
+
+impl NameId {
+    pub fn new(id: usize) -> Self {
+        NameId(id)
+    }
+
+    pub fn id(&self) -> usize {
+        self.0
+    }
+}
+
+pub struct NameStack {
+    next_sym: usize,
+    stack: Vec<HashMap<String, NameId>>,
+}
+
+impl NameStack {
+    pub fn new() -> Self {
+        NameStack {
+            next_sym: 0,
+            stack: vec![Default::default()],
+        }
+    }
+
+    pub fn push(&mut self, syms: HashMap<String, NameId>) {
+        self.stack.push(syms);
+    }
+
+    pub fn push_default(&mut self) {
+        self.push(Default::default());
+    }
+
+    pub fn pop(&mut self) -> Option<HashMap<String, NameId>> {
+        self.stack.pop()
+    }
+
+    pub fn add(&mut self, name: String) -> NameId {
+        let next_sym = NameId::new(self.next_sym);
+        let sym = *self.locals_mut().entry(name).or_insert(next_sym);
+        if sym.id() == self.next_sym {
+            self.next_sym += 1;
+        }
+        sym
+    }
+
+    /// Searches the top level of the symbol stack for the symbol with the supplied name.
+    pub fn get_local(&self, name: &str) -> Option<NameId> {
+        self.locals().get(name).copied()
+    }
+
+    /// Searches the stack from top to bottom for the symbol with the given name.
+    pub fn get_scoped(&self, name: &str) -> Option<NameId> {
+        self.stack
+            .iter()
+            .rev()
+            .filter_map(|locals| locals.get(name))
+            .next()
+            .copied()
+    }
+
+    pub fn root(&self) -> &HashMap<String, NameId> {
+        self.stack.first().expect("no root name map")
+    }
+
+    pub fn root_mut(&mut self) -> &mut HashMap<String, NameId> {
+        self.stack.first_mut().expect("no root name map")
+    }
+
+    pub fn locals(&self) -> &HashMap<String, NameId> {
+        self.stack.last().expect("no local name map")
+    }
+
+    pub fn locals_mut(&mut self) -> &mut HashMap<String, NameId> {
+        self.stack.last_mut().expect("no local name map")
+    }
+}
+
+/// Collect local names and push them to the top layer of the name stack.
+pub struct CollectNames<'c, 't: 'c> {
+    ctx: &'c mut Ctx<'t>,
+}
+
+impl<'c, 't: 'c> CollectNames<'c, 't> {
+    pub fn new(ctx: &'c mut Ctx<'t>) -> Self {
+        CollectNames { ctx }
+    }
+
+    pub fn collect(&mut self, stmts: &Vec<Stmt>) {
+        for stmt in stmts.iter() {
+            self.visit_stmt(stmt);
+        }
+    }
+
+    fn visit_base_expr(&mut self, expr: &BaseExpr) {
+        match &expr.kind {
+            BaseExprKind::Ident => {
+                let name = expr.text_at(self.ctx.text()).to_string();
+                self.ctx.name_stack_mut().add(name);
+            }
+            BaseExprKind::List(l) | BaseExprKind::Tuple(l) => {
+                l.iter().for_each(|expr| self.visit_expr(expr));
+            }
+            BaseExprKind::Object(o) => {
+                o.iter().for_each(|(key, value)| {
+                    self.visit_expr(key);
+                    self.visit_expr(value);
+                });
+            }
+            _ => { /* no-op */ }
+        }
+    }
+}
+
+impl Visit for CollectNames<'_, '_> {
+    type Out = ();
+
+    fn visit_expr(&mut self, expr: &Expr) -> Self::Out {
+        match expr {
+            Expr::Bin(b) => {
+                self.visit_expr(&b.lhs);
+                // don't descend into dot-expressions - these are not names, but symbols
+                if b.op != BinOp::Dot {
+                    self.visit_expr(&b.rhs);
+                }
+            }
+            Expr::Un(u) => {
+                self.visit_expr(&u.expr);
+            }
+            Expr::FunCall(f) => {
+                self.visit_expr(&f.expr);
+                f.args.iter().for_each(|expr| self.visit_expr(expr));
+            }
+            Expr::Index(i) => {
+                self.visit_expr(&i.expr);
+                self.visit_expr(&i.index);
+            }
+            Expr::Fun(f) => { /* no-op */ }
+            Expr::Base(b) => self.visit_base_expr(b),
+        }
+    }
+
+    fn visit_stmt(&mut self, stmt: &Stmt) -> Self::Out {
+        match stmt {
+            Stmt::Assign(AssignStmt { lhs, rhs, .. }) => {
+                self.visit_expr(lhs);
+                self.visit_expr(rhs);
+            }
+            Stmt::Expr(expr) => {
+                self.visit_expr(expr);
+            }
+        }
+    }
+}

src/compile/sym.rs

@@ -1,16 +0,0 @@
-use crate::obj::Sym;
-use std::collections::HashMap;
-
-pub struct SymStack {
-    syms: HashMap<String, Sym>,
-    stack: Vec<Vec<Sym>>,
-}
-
-impl SymStack {
-    pub fn new() -> Self {
-        SymStack {
-            syms: Default::default(),
-            stack: vec![Default::default()],
-        }
-    }
-}

src/compile/visit.rs

@@ -0,0 +1,29 @@
+use crate::syn::ast::{Stmt, Expr};
+
+pub trait Visit {
+    type Out;
+    fn visit<A: Accept<Self>>(&mut self, acceptor: &A) -> Self::Out
+        where Self: Sized
+    {
+        acceptor.accept(self)
+    }
+
+    fn visit_stmt(&mut self, stmt: &Stmt) -> Self::Out;
+    fn visit_expr(&mut self, expr: &Expr) -> Self::Out;
+}
+
+pub trait Accept<V: Visit> {
+    fn accept(&self, visitor: &mut V) -> V::Out;
+}
+
+impl<V: Visit> Accept<V> for Stmt {
+    fn accept(&self, visitor: &mut V) -> V::Out {
+        visitor.visit_stmt(self)
+    }
+}
+
+impl<V: Visit> Accept<V> for Expr {
+    fn accept(&self, visitor: &mut V) -> V::Out {
+        visitor.visit_expr(self)
+    }
+}

src/main.rs

@@ -40,6 +40,17 @@ fn main() -> Result<()> {
     let opt = Options::from_args();
     let text = fs::read_to_string(&opt.input)?;
     let mut parser = Parser::try_from(text.as_str())?;
-    println!("{:#?}", parser.next_body()?);
+    let ast = parser.next_body()?;
+    //println!("{:#?}", ast);
+    
+    let mut ctx = compile::Ctx::new(text.as_str());
+    ctx.name_stack_mut().push_default();
+    {
+        let mut collect_names = compile::name::CollectNames::new(&mut ctx);
+        collect_names.collect(&ast);
+    }
+    let names = ctx.name_stack_mut().pop().unwrap();
+    println!("{:#?}", names);
+    
     Ok(())
 }

src/syn/ast.rs

@@ -1,6 +1,21 @@
 use crate::syn::{op::*, span::*};
 use derivative::Derivative;
 
+pub mod prelude {
+    pub use super::{
+        Stmt,
+        AssignStmt,
+        Expr,
+        BinExpr,
+        UnExpr,
+        FunCallExpr,
+        IndexExpr,
+        FunExpr,
+        BaseExpr,
+        BaseExprKind
+    };
+}
+
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub enum Stmt {
     Assign(AssignStmt),