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-rw-r--r--src/grammar/expressions.rs56
1 files changed, 54 insertions, 2 deletions
diff --git a/src/grammar/expressions.rs b/src/grammar/expressions.rs
index c68419929..6506892e1 100644
--- a/src/grammar/expressions.rs
+++ b/src/grammar/expressions.rs
@@ -27,6 +27,7 @@ pub(super) fn literal(p: &mut Parser) -> Option<CompletedMarker> {
27} 27}
28 28
29const EXPR_FIRST: TokenSet = PREFIX_EXPR_FIRST; 29const EXPR_FIRST: TokenSet = PREFIX_EXPR_FIRST;
30
30pub(super) fn expr(p: &mut Parser) { 31pub(super) fn expr(p: &mut Parser) {
31 let mut lhs = match prefix_expr(p) { 32 let mut lhs = match prefix_expr(p) {
32 Some(lhs) => lhs, 33 Some(lhs) => lhs,
@@ -87,6 +88,7 @@ const PREFIX_EXPR_FIRST: TokenSet =
87 token_set![AMPERSAND, STAR, EXCL], 88 token_set![AMPERSAND, STAR, EXCL],
88 ATOM_EXPR_FIRST, 89 ATOM_EXPR_FIRST,
89 ]; 90 ];
91
90fn prefix_expr(p: &mut Parser) -> Option<CompletedMarker> { 92fn prefix_expr(p: &mut Parser) -> Option<CompletedMarker> {
91 let done = match p.current() { 93 let done = match p.current() {
92 AMPERSAND => ref_expr(p), 94 AMPERSAND => ref_expr(p),
@@ -140,6 +142,7 @@ const ATOM_EXPR_FIRST: TokenSet =
140 LITERAL_FIRST, 142 LITERAL_FIRST,
141 token_set![L_PAREN, PIPE, MOVE_KW, IF_KW, UNSAFE_KW, L_CURLY, RETURN_KW], 143 token_set![L_PAREN, PIPE, MOVE_KW, IF_KW, UNSAFE_KW, L_CURLY, RETURN_KW],
142 ]; 144 ];
145
143fn atom_expr(p: &mut Parser) -> Option<CompletedMarker> { 146fn atom_expr(p: &mut Parser) -> Option<CompletedMarker> {
144 match literal(p) { 147 match literal(p) {
145 Some(m) => return Some(m), 148 Some(m) => return Some(m),
@@ -154,6 +157,7 @@ fn atom_expr(p: &mut Parser) -> Option<CompletedMarker> {
154 PIPE => lambda_expr(p), 157 PIPE => lambda_expr(p),
155 MOVE_KW if la == PIPE => lambda_expr(p), 158 MOVE_KW if la == PIPE => lambda_expr(p),
156 IF_KW => if_expr(p), 159 IF_KW => if_expr(p),
160 MATCH_KW => match_expr(p),
157 UNSAFE_KW if la == L_CURLY => block_expr(p), 161 UNSAFE_KW if la == L_CURLY => block_expr(p),
158 L_CURLY => block_expr(p), 162 L_CURLY => block_expr(p),
159 RETURN_KW => return_expr(p), 163 RETURN_KW => return_expr(p),
@@ -202,8 +206,7 @@ fn lambda_expr(p: &mut Parser) -> CompletedMarker {
202fn if_expr(p: &mut Parser) -> CompletedMarker { 206fn if_expr(p: &mut Parser) -> CompletedMarker {
203 assert!(p.at(IF_KW)); 207 assert!(p.at(IF_KW));
204 let m = p.start(); 208 let m = p.start();
205 p.bump(); 209 if_head(p);
206 expr(p);
207 block(p); 210 block(p);
208 if p.at(ELSE_KW) { 211 if p.at(ELSE_KW) {
209 p.bump(); 212 p.bump();
@@ -216,6 +219,55 @@ fn if_expr(p: &mut Parser) -> CompletedMarker {
216 m.complete(p, IF_EXPR) 219 m.complete(p, IF_EXPR)
217} 220}
218 221
222fn if_head(p: &mut Parser) {
223 assert!(p.at(IF_KW));
224 p.bump();
225 expr(p);
226}
227
228// test match_expr
229// fn foo() {
230// match () { };
231// }
232fn match_expr(p: &mut Parser) -> CompletedMarker {
233 assert!(p.at(MATCH_KW));
234 let m = p.start();
235 p.bump();
236 expr(p);
237 p.eat(L_CURLY);
238 while !p.at(EOF) && !p.at(R_CURLY) {
239 match_arm(p);
240 if !p.at(R_CURLY) {
241 p.expect(COMMA);
242 }
243 }
244 p.expect(R_CURLY);
245 m.complete(p, MATCH_EXPR)
246}
247
248// test match_arm
249// fn foo() {
250// match () {
251// _ => (),
252// X | Y if Z => (),
253// };
254// }
255fn match_arm(p: &mut Parser) {
256 let m = p.start();
257 loop {
258 patterns::pattern(p);
259 if !p.eat(PIPE) {
260 break;
261 }
262 }
263 if p.at(IF_KW) {
264 if_head(p)
265 }
266 p.expect(FAT_ARROW);
267 expr(p);
268 m.complete(p, MATCH_ARM);
269}
270
219// test block_expr 271// test block_expr
220// fn foo() { 272// fn foo() {
221// {}; 273// {};