From ed28f1c1bc94dd0c5a6bffd77b71155bdf82d906 Mon Sep 17 00:00:00 2001
From: Chris Wong <lambda.fairy@gmail.com>
Date: Fri, 27 Feb 2015 09:27:45 +1300
Subject: [PATCH] Implement if/else
---
maud_macros/src/parse.rs | 44 ++++++++++++++++++++++++++++++++++++--
maud_macros/tests/tests.rs | 20 +++++++++++++++++
2 files changed, 62 insertions(+), 2 deletions(-)
diff --git a/maud_macros/src/parse.rs b/maud_macros/src/parse.rs
index 261ec3a..0df8e59 100644
--- a/maud_macros/src/parse.rs
+++ b/maud_macros/src/parse.rs
@@ -4,7 +4,7 @@ use syntax::codemap::Span;
use syntax::ext::base::ExtCtxt;
use syntax::parse;
use syntax::parse::parser::Parser as RustParser;
-use syntax::parse::token;
+use syntax::parse::token::{self, DelimToken};
use syntax::ptr::P;
use super::render::{Escape, Renderer};
@@ -97,6 +97,11 @@ impl<'cx, 's, 'i> Parser<'cx, 's, 'i> {
self.shift(1);
self.literal(tt, false)
},
+ // If
+ [dollar!(), ident!(sp, name), ..] if name.as_str() == "if" => {
+ self.shift(2);
+ self.if_expr(sp);
+ },
// Splice
[ref tt @ dollar!(), dollar!(), ..] => {
self.shift(2);
@@ -140,6 +145,41 @@ impl<'cx, 's, 'i> Parser<'cx, 's, 'i> {
}
}
+ fn if_expr(&mut self, sp: Span) {
+ let mut cond = vec![];
+ let if_body;
+ loop { match self.input {
+ [TtDelimited(sp, ref d), ..] if d.delim == DelimToken::Brace => {
+ self.shift(1);
+ if_body = self.block(sp, &d.tts);
+ break;
+ },
+ [ref tt, ..] => {
+ self.shift(1);
+ cond.push(tt.clone());
+ },
+ [] => self.render.cx.span_fatal(sp, "expected body for this $if"),
+ }}
+ let cond = self.new_rust_parser(cond).parse_expr();
+ let else_body = match self.input {
+ [dollar!(), ident!(name), ..] if name.as_str() == "else" => {
+ self.shift(2);
+ let else_body = {
+ // Parse a single markup, but capture the result rather
+ // than emitting it right away
+ let mut render = self.render.fork();
+ mem::swap(&mut self.render, &mut render);
+ self.markup();
+ mem::swap(&mut self.render, &mut render);
+ render.into_stmts()
+ };
+ Some(else_body)
+ },
+ _ => None,
+ };
+ self.render.emit_if(cond, if_body, else_body);
+ }
+
fn splice(&mut self, sp: Span) -> P<Expr> {
let mut tts = vec![];
// First, munch a single token tree
@@ -194,7 +234,7 @@ impl<'cx, 's, 'i> Parser<'cx, 's, 'i> {
self.render.attribute_start(name.as_str());
{
// Parse a value under an attribute context
- let in_attr = true;
+ let mut in_attr = true;
mem::swap(&mut self.in_attr, &mut in_attr);
self.markup();
mem::swap(&mut self.in_attr, &mut in_attr);
diff --git a/maud_macros/tests/tests.rs b/maud_macros/tests/tests.rs
index 5ffffb2..56c0f0c 100644
--- a/maud_macros/tests/tests.rs
+++ b/maud_macros/tests/tests.rs
@@ -182,3 +182,23 @@ fn issue_1() {
let markup = html! { "Test" };
let _ = markup.to_string();
}
+
+mod control {
+ #[test]
+ fn if_expr() {
+ for (number, &name) in (1..4).zip(["one", "two", "three"].iter()) {
+ let s = html! {
+ $if number == 1 {
+ "one"
+ } $else $if number == 2 {
+ "two"
+ } $else $if number == 3 {
+ "three"
+ } $else {
+ "oh noes"
+ }
+ }.to_string();
+ assert_eq!(s, name);
+ }
+ }
+}