From 333eb46c3a46f7605dbf17aaec5de6bce58901b8 Mon Sep 17 00:00:00 2001
From: Chris Wong <lambda.fairy@gmail.com>
Date: Sun, 15 Mar 2015 16:23:19 +1300
Subject: [PATCH] Support `if let`
---
maud_macros/src/parse.rs | 8 ++++----
maud_macros/src/render.rs | 8 ++++++--
maud_macros/tests/tests.rs | 14 ++++++++++++++
3 files changed, 24 insertions(+), 6 deletions(-)
diff --git a/maud_macros/src/parse.rs b/maud_macros/src/parse.rs
index 26c1460..0fba573 100644
--- a/maud_macros/src/parse.rs
+++ b/maud_macros/src/parse.rs
@@ -1,5 +1,6 @@
use std::mem;
use syntax::ast::{Expr, ExprParen, Lit, Stmt, TokenTree, TtDelimited, TtToken};
+use syntax::ext::quote::rt::ToTokens;
use syntax::codemap::Span;
use syntax::ext::base::ExtCtxt;
use syntax::parse;
@@ -152,7 +153,7 @@ impl<'cx, 's, 'i> Parser<'cx, 's, 'i> {
fn if_expr(&mut self, sp: Span) {
// Parse the initial if
- let mut cond_tts = vec![];
+ let mut if_cond = vec![];
let if_body;
loop { match self.input {
[TtDelimited(sp, ref d), ..] if d.delim == DelimToken::Brace => {
@@ -162,11 +163,10 @@ impl<'cx, 's, 'i> Parser<'cx, 's, 'i> {
},
[ref tt, ..] => {
self.shift(1);
- cond_tts.push(tt.clone());
+ if_cond.push(tt.clone());
},
[] => self.render.cx.span_fatal(sp, "expected body for this $if"),
}}
- let if_cond = self.new_rust_parser(cond_tts).parse_expr();
// Parse the (optional) else
let else_body = match self.input {
[dollar!(), ident!(else_), ..] if else_.as_str() == "else" => {
@@ -298,7 +298,7 @@ impl<'cx, 's, 'i> Parser<'cx, 's, 'i> {
self.shift(1);
let cond = self.splice(tt.get_span());
// Silence "unnecessary parentheses" warnings
- let cond = strip_outer_parens(cond);
+ let cond = strip_outer_parens(cond).to_tokens(self.render.cx);
let body = {
let mut r = self.render.fork();
r.attribute_empty(name.as_str());
diff --git a/maud_macros/src/render.rs b/maud_macros/src/render.rs
index 20b9810..de3972f 100644
--- a/maud_macros/src/render.rs
+++ b/maud_macros/src/render.rs
@@ -1,4 +1,4 @@
-use syntax::ast::{Expr, Ident, Pat, Stmt};
+use syntax::ast::{Expr, Ident, Pat, Stmt, TokenTree};
use syntax::ext::base::ExtCtxt;
use syntax::ext::build::AstBuilder;
use syntax::parse::token;
@@ -126,7 +126,11 @@ impl<'cx, 's> Renderer<'cx, 's> {
self.write(">");
}
- pub fn emit_if(&mut self, if_cond: P<Expr>, if_body: Vec<P<Stmt>>,
+ /// Emit an `if` expression.
+ ///
+ /// The condition is a token tree (not an expression) so we don't
+ /// need to special-case `if let`.
+ pub fn emit_if(&mut self, if_cond: Vec<TokenTree>, if_body: Vec<P<Stmt>>,
else_body: Option<Vec<P<Stmt>>>) {
let stmt = match else_body {
None => quote_stmt!(self.cx, if $if_cond { $if_body }),
diff --git a/maud_macros/tests/tests.rs b/maud_macros/tests/tests.rs
index 4ce1763..8defeec 100644
--- a/maud_macros/tests/tests.rs
+++ b/maud_macros/tests/tests.rs
@@ -202,6 +202,20 @@ mod control {
}
}
+ #[test]
+ fn if_let() {
+ for &(input, output) in [(Some("yay"), "yay"), (None, "oh noes")].iter() {
+ let s = html! {
+ $if let Some(value) = input {
+ $value
+ } $else {
+ "oh noes"
+ }
+ }.to_string();
+ assert_eq!(s, output);
+ }
+ }
+
#[test]
fn for_expr() {
let ponies = ["Apple Bloom", "Scootaloo", "Sweetie Belle"];