Move pretty-printing to its own module.

src/syntax.rs

@@ -2,6 +2,7 @@ use codespan_reporting::{diagnostic::Diagnostic, files::SimpleFiles};
 use lalrpop_util::lalrpop_mod;
 use logos::Logos;
 
+pub mod ast;
 mod location;
 mod simplify;
 mod tokens;
@@ -10,7 +11,7 @@ lalrpop_mod!(
     parser,
     "/syntax/parser.rs"
 );
-pub mod ast;
+mod pretty;
 mod validate;
 
 pub use crate::syntax::ast::*;

src/syntax/ast.rs

@@ -1,59 +1,18 @@
 use crate::syntax::Location;
-use pretty::{DocAllocator, DocBuilder, Pretty};
 
-static BINARY_OPERATORS: &[&str] = &["+", "-", "*", "/"];
+pub static BINARY_OPERATORS: &[&str] = &["+", "-", "*", "/"];
 
 #[derive(Debug, PartialEq)]
 pub struct Program {
     pub statements: Vec<Statement>,
 }
 
-impl<'a, 'b, D, A> Pretty<'a, D, A> for &'b Program
-where
-    A: 'a,
-    D: ?Sized + DocAllocator<'a, A>,
-{
-    fn pretty(self, allocator: &'a D) -> DocBuilder<'a, D, A> {
-        let mut result = allocator.nil();
-
-        for stmt in self.statements.iter() {
-            result = result
-                .append(stmt.pretty(allocator))
-                .append(allocator.text(";"))
-                .append(allocator.hardline());
-        }
-
-        result
-    }
-}
-
 #[derive(Debug, PartialEq)]
 pub enum Statement {
     Binding(Location, String, Expression),
     Print(Location, String),
 }
 
-impl<'a, 'b, D, A> Pretty<'a, D, A> for &'b Statement
-where
-    A: 'a,
-    D: ?Sized + DocAllocator<'a, A>,
-{
-    fn pretty(self, allocator: &'a D) -> DocBuilder<'a, D, A> {
-        match self {
-            Statement::Binding(_, var, expr) => allocator
-                .text(var.to_string())
-                .append(allocator.space())
-                .append(allocator.text("="))
-                .append(allocator.space())
-                .append(expr.pretty(allocator)),
-            Statement::Print(_, var) => allocator
-                .text("print")
-                .append(allocator.space())
-                .append(allocator.text(var.to_string())),
-        }
-    }
-}
-
 #[derive(Debug, PartialEq)]
 pub enum Expression {
     Value(Location, Value),
@@ -61,79 +20,7 @@ pub enum Expression {
     Primitive(Location, String, Vec<Expression>),
 }
 
-impl<'a, 'b, D, A> Pretty<'a, D, A> for &'b Expression
-where
-    A: 'a,
-    D: ?Sized + DocAllocator<'a, A>,
-{
-    fn pretty(self, allocator: &'a D) -> DocBuilder<'a, D, A> {
-        match self {
-            Expression::Value(_, val) => val.pretty(allocator),
-            Expression::Reference(_, var) => allocator.text(var.to_string()),
-            Expression::Primitive(_, op, exprs) if BINARY_OPERATORS.contains(&op.as_ref()) => {
-                assert_eq!(
-                    exprs.len(),
-                    2,
-                    "Found binary operator with {} components?",
-                    exprs.len()
-                );
-
-                let left = exprs[0].pretty(allocator);
-                let right = exprs[1].pretty(allocator);
-
-                left.append(allocator.space())
-                    .append(allocator.text(op.to_string()))
-                    .append(allocator.space())
-                    .append(right)
-                    .parens()
-            }
-            Expression::Primitive(_, op, exprs) => {
-                let call = allocator.text(op.to_string());
-                let args = exprs.iter().map(|x| x.pretty(allocator));
-                let comma_sepped_args = allocator.intersperse(args, CommaSep {});
-                call.append(comma_sepped_args.parens())
-            }
-        }
-    }
-}
-
 #[derive(Debug, PartialEq, Eq)]
 pub enum Value {
     Number(Option<u8>, i64),
 }
-
-impl<'a, 'b, D, A> Pretty<'a, D, A> for &'b Value
-where
-    A: 'a,
-    D: ?Sized + DocAllocator<'a, A>,
-{
-    fn pretty(self, allocator: &'a D) -> DocBuilder<'a, D, A> {
-        match self {
-            Value::Number(opt_base, value) => {
-                let value_str = match opt_base {
-                    None => format!("{}", value),
-                    Some(2) => format!("0b{:b}", value),
-                    Some(8) => format!("0o{:o}", value),
-                    Some(10) => format!("0d{}", value),
-                    Some(16) => format!("0x{:x}", value),
-                    Some(_) => format!("!!{:x}!!", value),
-                };
-
-                allocator.text(value_str)
-            }
-        }
-    }
-}
-
-#[derive(Clone, Copy)]
-struct CommaSep {}
-
-impl<'a, D, A> Pretty<'a, D, A> for CommaSep
-where
-    A: 'a,
-    D: ?Sized + DocAllocator<'a, A>,
-{
-    fn pretty(self, allocator: &'a D) -> DocBuilder<'a, D, A> {
-        allocator.text(",").append(allocator.space())
-    }
-}

src/syntax/pretty.rs

@@ -0,0 +1,114 @@
+use pretty::{Pretty, DocAllocator, DocBuilder};
+use crate::syntax::ast::{Program, Statement, Expression, Value, BINARY_OPERATORS};
+
+impl<'a, 'b, D, A> Pretty<'a, D, A> for &'b Program
+where
+    A: 'a,
+    D: ?Sized + DocAllocator<'a, A>,
+{
+    fn pretty(self, allocator: &'a D) -> DocBuilder<'a, D, A> {
+        let mut result = allocator.nil();
+
+        for stmt in self.statements.iter() {
+            result = result
+                .append(stmt.pretty(allocator))
+                .append(allocator.text(";"))
+                .append(allocator.hardline());
+        }
+
+        result
+    }
+}
+
+impl<'a, 'b, D, A> Pretty<'a, D, A> for &'b Statement
+where
+    A: 'a,
+    D: ?Sized + DocAllocator<'a, A>,
+{
+    fn pretty(self, allocator: &'a D) -> DocBuilder<'a, D, A> {
+        match self {
+            Statement::Binding(_, var, expr) => allocator
+                .text(var.to_string())
+                .append(allocator.space())
+                .append(allocator.text("="))
+                .append(allocator.space())
+                .append(expr.pretty(allocator)),
+            Statement::Print(_, var) => allocator
+                .text("print")
+                .append(allocator.space())
+                .append(allocator.text(var.to_string())),
+        }
+    }
+}
+
+impl<'a, 'b, D, A> Pretty<'a, D, A> for &'b Expression
+where
+    A: 'a,
+    D: ?Sized + DocAllocator<'a, A>,
+{
+    fn pretty(self, allocator: &'a D) -> DocBuilder<'a, D, A> {
+        match self {
+            Expression::Value(_, val) => val.pretty(allocator),
+            Expression::Reference(_, var) => allocator.text(var.to_string()),
+            Expression::Primitive(_, op, exprs) if BINARY_OPERATORS.contains(&op.as_ref()) => {
+                assert_eq!(
+                    exprs.len(),
+                    2,
+                    "Found binary operator with {} components?",
+                    exprs.len()
+                );
+
+                let left = exprs[0].pretty(allocator);
+                let right = exprs[1].pretty(allocator);
+
+                left.append(allocator.space())
+                    .append(allocator.text(op.to_string()))
+                    .append(allocator.space())
+                    .append(right)
+                    .parens()
+            }
+            Expression::Primitive(_, op, exprs) => {
+                let call = allocator.text(op.to_string());
+                let args = exprs.iter().map(|x| x.pretty(allocator));
+                let comma_sepped_args = allocator.intersperse(args, CommaSep {});
+                call.append(comma_sepped_args.parens())
+            }
+        }
+    }
+}
+
+impl<'a, 'b, D, A> Pretty<'a, D, A> for &'b Value
+where
+    A: 'a,
+    D: ?Sized + DocAllocator<'a, A>,
+{
+    fn pretty(self, allocator: &'a D) -> DocBuilder<'a, D, A> {
+        match self {
+            Value::Number(opt_base, value) => {
+                let value_str = match opt_base {
+                    None => format!("{}", value),
+                    Some(2) => format!("0b{:b}", value),
+                    Some(8) => format!("0o{:o}", value),
+                    Some(10) => format!("0d{}", value),
+                    Some(16) => format!("0x{:x}", value),
+                    Some(_) => format!("!!{:x}!!", value),
+                };
+
+                allocator.text(value_str)
+            }
+        }
+    }
+}
+
+#[derive(Clone, Copy)]
+struct CommaSep {}
+
+impl<'a, D, A> Pretty<'a, D, A> for CommaSep
+where
+    A: 'a,
+    D: ?Sized + DocAllocator<'a, A>,
+{
+    fn pretty(self, allocator: &'a D) -> DocBuilder<'a, D, A> {
+        allocator.text(",").append(allocator.space())
+    }
+}