From dca04006921cd070690db2ea5f66dcc770dcd302 Mon Sep 17 00:00:00 2001
From: Chris Wong <lambda.fairy@gmail.com>
Date: Thu, 29 Jan 2015 13:47:11 +1300
Subject: [PATCH] Implement toggleable boolean attributes
Closes #4
---
maud/src/lib.rs | 4 ++--
maud_macros/src/parse.rs | 44 +++++++++++++++++++++++++-------------
maud_macros/src/render.rs | 22 +++++++++++++++++--
maud_macros/tests/tests.rs | 18 +++++++++++++++-
4 files changed, 68 insertions(+), 20 deletions(-)
diff --git a/maud/src/lib.rs b/maud/src/lib.rs
index 85f1eb8..9ef2b45 100644
--- a/maud/src/lib.rs
+++ b/maud/src/lib.rs
@@ -99,7 +99,7 @@
//! html! {
//! form method="POST" {
//! label for="waffles" "Do you like waffles?"
-//! input name="waffles" type="checkbox" checked=! /
+//! input name="waffles" type="checkbox" checked? /
//! }
//! }
//! ```
@@ -114,7 +114,7 @@
//! Add attributes using the syntax `attr="value"`. Attributes must be
//! quoted: they are parsed as string literals.
//!
-//! To declare an empty attribute, use `!` for the value: `checked=!`.
+//! To declare an empty attribute, use a `?` suffix: `checked?`.
//!
//! ## Splices
//!
diff --git a/maud_macros/src/parse.rs b/maud_macros/src/parse.rs
index 31de992..c69df18 100644
--- a/maud_macros/src/parse.rs
+++ b/maud_macros/src/parse.rs
@@ -20,6 +20,9 @@ macro_rules! eq {
macro_rules! not {
() => (TtToken(_, token::Not))
}
+macro_rules! question {
+ () => (TtToken(_, token::Question))
+}
macro_rules! semi {
() => (TtToken(_, token::Semi))
}
@@ -90,11 +93,13 @@ impl<'cx, 's, 'i, 'r, 'o> Parser<'cx, 's, 'i, 'r, 'o> {
// Splice
[ref tt @ dollar!(), dollar!(), ..] => {
self.shift(2);
- self.splice(Escape::PassThru, tt.get_span())
+ let expr = self.splice(tt.get_span());
+ self.render.splice(expr, Escape::PassThru);
},
[ref tt @ dollar!(), ..] => {
self.shift(1);
- self.splice(Escape::Escape, tt.get_span())
+ let expr = self.splice(tt.get_span());
+ self.render.splice(expr, Escape::Escape);
},
// Element
[ident!(sp, name), ..] => {
@@ -127,7 +132,7 @@ impl<'cx, 's, 'i, 'r, 'o> Parser<'cx, 's, 'i, 'r, 'o> {
}
}
- fn splice(&mut self, escape: Escape, sp: Span) {
+ fn splice(&mut self, sp: Span) -> P<Expr> {
let mut tts = vec![];
// First, munch a single token tree
if let [ref tt, ..] = self.input {
@@ -151,10 +156,9 @@ impl<'cx, 's, 'i, 'r, 'o> Parser<'cx, 's, 'i, 'r, 'o> {
}
}
if tts.is_empty() {
- self.render.cx.span_err(sp, "expected expression for this splice");
+ self.render.cx.span_fatal(sp, "expected expression for this splice");
} else {
- let expr = self.new_rust_parser(tts).parse_expr();
- self.render.splice(expr, escape);
+ self.new_rust_parser(tts).parse_expr()
}
}
@@ -175,14 +179,10 @@ impl<'cx, 's, 'i, 'r, 'o> Parser<'cx, 's, 'i, 'r, 'o> {
}
fn attrs(&mut self) {
- while let [ident!(name), eq!(), ..] = self.input {
- self.shift(2);
- if let [not!(), ..] = self.input {
- // Empty attribute
- self.shift(1);
- self.render.attribute_empty(name.as_str());
- } else {
+ loop { match self.input {
+ [ident!(name), eq!(), ..] => {
// Non-empty attribute
+ self.shift(2);
self.render.attribute_start(name.as_str());
{
// Parse a value under an attribute context
@@ -192,8 +192,22 @@ impl<'cx, 's, 'i, 'r, 'o> Parser<'cx, 's, 'i, 'r, 'o> {
self.in_attr = old_in_attr;
}
self.render.attribute_end();
- }
- }
+ },
+ [ident!(name), question!(), ..] => {
+ // Empty attribute
+ self.shift(2);
+ if let [ref tt @ eq!(), ..] = self.input {
+ // Toggle the attribute based on a boolean expression
+ self.shift(1);
+ let expr = self.splice(tt.get_span());
+ self.render.attribute_empty_if(name.as_str(), expr);
+ } else {
+ // Write the attribute unconditionally
+ self.render.attribute_empty(name.as_str());
+ }
+ },
+ _ => return,
+ }}
}
fn block(&mut self, tts: &[TokenTree]) {
diff --git a/maud_macros/src/render.rs b/maud_macros/src/render.rs
index 0def710..09a2dd7 100644
--- a/maud_macros/src/render.rs
+++ b/maud_macros/src/render.rs
@@ -43,8 +43,13 @@ impl<'cx, 's, 'o> Renderer<'cx, 's, 'o> {
/// Push an expression statement, also wrapping it with `try!`.
fn push(&mut self, expr: P<Expr>) {
- let expr = self.cx.stmt_expr(self.cx.expr_try(expr.span, expr));
- self.stmts.push(expr);
+ let stmt = self.make_stmt(expr);
+ self.stmts.push(stmt);
+ }
+
+ /// Create an expression statement, also wrapping it with `try!`.
+ fn make_stmt(&mut self, expr: P<Expr>) -> P<Stmt> {
+ self.cx.stmt_expr(self.cx.expr_try(expr.span, expr))
}
/// Append a literal pre-escaped string.
@@ -94,6 +99,19 @@ impl<'cx, 's, 'o> Renderer<'cx, 's, 'o> {
self.write(name);
}
+ pub fn attribute_empty_if(&mut self, name: &str, expr: P<Expr>) {
+ let s: String = [" ", name].concat();
+ let s = &s[];
+ let w = self.w;
+ let expr = quote_expr!(self.cx,
+ if $expr {
+ $w.write_str($s)
+ } else {
+ Ok(())
+ });
+ self.push(expr);
+ }
+
pub fn attribute_end(&mut self) {
self.write("\"");
}
diff --git a/maud_macros/tests/tests.rs b/maud_macros/tests/tests.rs
index de054db..6834094 100644
--- a/maud_macros/tests/tests.rs
+++ b/maud_macros/tests/tests.rs
@@ -76,7 +76,7 @@ mod elements {
#[test]
fn empty_attributes() {
- let s = html! { div readonly=! input type="checkbox" checked=! / }.to_string();
+ let s = html! { div readonly? input type="checkbox" checked? / }.to_string();
assert_eq!(s, r#"<div readonly><input type="checkbox" checked></div>"#);
}
}
@@ -108,6 +108,22 @@ mod splices {
assert_eq!(s, "3628800");
}
+ #[test]
+ fn attributes() {
+ let rocks = true;
+ let s = html! {
+ input checked?=true /
+ input checked?=false /
+ input checked?=rocks /
+ input checked?=(!rocks) /
+ }.to_string();
+ assert_eq!(s, concat!(
+ r#"<input checked>"#,
+ r#"<input>"#,
+ r#"<input checked>"#,
+ r#"<input>"#));
+ }
+
static BEST_PONY: &'static str = "Pinkie Pie";
#[test]