parse.rkt (56571B)
1 #lang racket/base 2 (require (for-syntax racket/base 3 syntax/stx 4 syntax/private/id-table 5 syntax/keyword 6 racket/syntax 7 syntax/parse/private/minimatch 8 syntax/parse/private/rep-attrs 9 syntax/parse/private/rep-data 10 syntax/parse/private/rep-patterns 11 "rep.rkt" 12 syntax/parse/private/kws 13 "opt.rkt" 14 "txlift.rkt") 15 syntax/parse/private/keywords 16 racket/syntax 17 racket/stxparam 18 syntax/stx 19 stxparse-info/parse/private/residual ;; keep abs. path 20 "runtime.rkt" 21 stxparse-info/parse/private/runtime-reflect) ;; keep abs. path 22 23 ;; ============================================================ 24 25 (provide define-syntax-class 26 define-splicing-syntax-class 27 define-integrable-syntax-class 28 syntax-parse 29 syntax-parser 30 define/syntax-parse 31 syntax-parser/template 32 parser/rhs 33 define-eh-alternative-set 34 (for-syntax rhs->parser)) 35 36 (begin-for-syntax 37 ;; constant-desc : Syntax -> String/#f 38 (define (constant-desc stx) 39 (syntax-case stx (quote) 40 [(quote datum) 41 (let ([d (syntax-e #'datum)]) 42 (and (string? d) d))] 43 [expr 44 (let ([d (syntax-e #'expr)]) 45 (and (string? d) 46 (free-identifier=? #'#%datum (datum->syntax #'expr '#%datum)) 47 d))])) 48 49 (define (tx:define-*-syntax-class stx splicing?) 50 (syntax-case stx () 51 [(_ header . rhss) 52 (parameterize ((current-syntax-context stx)) 53 (let-values ([(name formals arity) 54 (let ([p (check-stxclass-header #'header stx)]) 55 (values (car p) (cadr p) (caddr p)))]) 56 (let ([the-rhs (parse-rhs #'rhss #f splicing? #:context stx)]) 57 (with-syntax ([name name] 58 [formals formals] 59 [desc (cond [(rhs-description the-rhs) => constant-desc] 60 [else (symbol->string (syntax-e name))])] 61 [parser (generate-temporary (format-symbol "parse-~a" name))] 62 [arity arity] 63 [attrs (rhs-attrs the-rhs)] 64 [commit? (rhs-commit? the-rhs)] 65 [delimit-cut? (rhs-delimit-cut? the-rhs)]) 66 #`(begin (define-syntax name 67 (stxclass 'name 'arity 68 'attrs 69 (quote-syntax parser) 70 '#,splicing? 71 (scopts (length 'attrs) 'commit? 'delimit-cut? desc) 72 #f)) 73 (define-values (parser) 74 (parser/rhs name formals attrs rhss #,splicing? #,stx)))))))]))) 75 76 (define-syntax define-syntax-class 77 (lambda (stx) (tx:define-*-syntax-class stx #f))) 78 (define-syntax define-splicing-syntax-class 79 (lambda (stx) (tx:define-*-syntax-class stx #t))) 80 81 (define-syntax (define-integrable-syntax-class stx) 82 (syntax-case stx (quote) 83 [(_ name (quote description) predicate) 84 (with-syntax ([parser (generate-temporary (format-symbol "parse-~a" (syntax-e #'name)))] 85 [no-arity no-arity]) 86 #'(begin (define-syntax name 87 (stxclass 'name no-arity '() 88 (quote-syntax parser) 89 #f 90 (scopts 0 #t #t 'description) 91 (quote-syntax predicate))) 92 (define (parser x cx pr es undos fh0 cp0 rl success) 93 (if (predicate x) 94 (success fh0 undos) 95 (let ([es (es-add-thing pr 'description #t rl es)]) 96 (fh0 undos (failure* pr es)))))))])) 97 98 (define-syntax (parser/rhs stx) 99 (syntax-case stx () 100 [(parser/rhs name formals relsattrs rhss splicing? ctx) 101 (with-disappeared-uses 102 (let () 103 (define the-rhs 104 (parameterize ((current-syntax-context #'ctx)) 105 (parse-rhs #'rhss (syntax->datum #'relsattrs) (syntax-e #'splicing?) 106 #:context #'ctx))) 107 (rhs->parser #'name #'formals #'relsattrs the-rhs (syntax-e #'splicing?) #'ctx)))])) 108 109 (begin-for-syntax 110 (define (rhs->parser name formals relsattrs the-rhs splicing? [ctx #f]) 111 (define-values (transparent? description variants defs commit? delimit-cut?) 112 (match the-rhs 113 [(rhs _ transparent? description variants defs commit? delimit-cut?) 114 (values transparent? description variants defs commit? delimit-cut?)])) 115 (define vdefss (map variant-definitions variants)) 116 (define formals* (rewrite-formals formals #'x #'rl)) 117 (define patterns (map variant-pattern variants)) 118 (define no-fail? 119 (and (not splicing?) ;; FIXME: commit? needed? 120 (patterns-cannot-fail? patterns))) 121 (when no-fail? (log-syntax-parse-debug "(stxclass) cannot fail: ~e" ctx)) 122 (define body 123 (cond [(null? patterns) 124 #'(fail (failure* pr es))] 125 [splicing? 126 (with-syntax ([(alternative ...) 127 (for/list ([pattern (in-list patterns)]) 128 (with-syntax ([pattern pattern] 129 [relsattrs relsattrs] 130 [iattrs (pattern-attrs pattern)] 131 [commit? commit?] 132 [result-pr 133 (if transparent? 134 #'rest-pr 135 #'(ps-pop-opaque rest-pr))]) 136 #'(parse:H x cx rest-x rest-cx rest-pr pattern pr es 137 (variant-success relsattrs iattrs (rest-x rest-cx result-pr) 138 success cp0 commit?))))]) 139 #'(try alternative ...))] 140 [else 141 (with-syntax ([matrix 142 (optimize-matrix 143 (for/list ([pattern (in-list patterns)]) 144 (with-syntax ([iattrs (pattern-attrs pattern)] 145 [relsattrs relsattrs] 146 [commit? commit?]) 147 (pk1 (list pattern) 148 #'(variant-success relsattrs iattrs () 149 success cp0 commit?)))))]) 150 #'(parse:matrix ((x cx pr es)) matrix))])) 151 (with-syntax ([formals* formals*] 152 [(def ...) defs] 153 [((vdef ...) ...) vdefss] 154 [description (or description (symbol->string (syntax-e name)))] 155 [transparent? transparent?] 156 [delimit-cut? delimit-cut?] 157 [body body]) 158 #`(lambda (x cx pr es undos fh0 cp0 rl success . formals*) 159 (with ([this-syntax x] 160 [this-role rl]) 161 def ... 162 vdef ... ... 163 (#%expression 164 (syntax-parameterize ((this-context-syntax 165 (syntax-rules () 166 [(tbs) (ps-context-syntax pr)]))) 167 (let ([es (es-add-thing pr description 'transparent? rl 168 #,(if no-fail? #'#f #'es))] 169 [pr (if 'transparent? pr (ps-add-opaque pr))]) 170 (with ([fail-handler fh0] 171 [cut-prompt cp0] 172 [undo-stack undos]) 173 ;; Update the prompt, if required 174 ;; FIXME: can be optimized away if no cut exposed within variants 175 (with-maybe-delimit-cut delimit-cut? 176 body)))))))))) 177 178 (define-syntax (syntax-parse stx) 179 (syntax-case stx () 180 [(syntax-parse stx-expr . clauses) 181 (quasisyntax/loc stx 182 (let ([x (datum->syntax #f stx-expr)]) 183 (with ([this-syntax x]) 184 (parse:clauses x clauses body-sequence #,((make-syntax-introducer) stx)))))])) 185 186 (define-syntax (syntax-parser stx) 187 (syntax-case stx () 188 [(syntax-parser . clauses) 189 (quasisyntax/loc stx 190 (lambda (x) 191 (let ([x (datum->syntax #f x)]) 192 (with ([this-syntax x]) 193 (parse:clauses x clauses body-sequence #,((make-syntax-introducer) stx))))))])) 194 195 (define-syntax (syntax-parser/template stx) 196 (syntax-case stx () 197 [(syntax-parser/template ctx . clauses) 198 (quasisyntax/loc stx 199 (lambda (x) 200 (let ([x (datum->syntax #f x)]) 201 (with ([this-syntax x]) 202 (parse:clauses x clauses one-template ctx)))))])) 203 204 (define-syntax (define/syntax-parse stx) 205 (syntax-case stx () 206 [(define/syntax-parse pattern . rest) 207 (with-disappeared-uses 208 (let-values ([(rest pattern defs) 209 (parse-pattern+sides #'pattern 210 #'rest 211 #:splicing? #f 212 #:decls (new-declenv null) 213 #:context stx)]) 214 (let ([expr 215 (syntax-case rest () 216 [( expr ) #'expr] 217 [_ (raise-syntax-error #f "bad syntax" stx)])] 218 [attrs (pattern-attrs pattern)]) 219 (with-syntax ([(a ...) attrs] 220 [(#s(attr name _ _) ...) attrs] 221 [pattern pattern] 222 [(def ...) defs] 223 [expr expr]) 224 #'(defattrs/unpack (a ...) 225 (let* ([x (datum->syntax #f expr)] 226 [cx x] 227 [pr (ps-empty x x)] 228 [es #f] 229 [fh0 (syntax-patterns-fail x)]) 230 (parameterize ((current-syntax-context x)) 231 def ... 232 (#%expression 233 (with ([fail-handler fh0] 234 [cut-prompt fh0] 235 [undo-stack null]) 236 (parse:S x cx pattern pr es 237 (list (attribute name) ...)))))))))))])) 238 239 ;; ============================================================ 240 241 #| 242 Parsing protocols: 243 244 (parse:<X> <X-args> pr es success-expr) : Ans 245 246 <S-args> : x cx 247 <H-args> : x cx rest-x rest-cx rest-pr 248 <EH-args> : x cx ??? 249 <A-args> : x cx 250 251 x is term to parse, usually syntax but can be pair/null (stx-list?) in cdr patterns 252 cx is most recent syntax object: if x must be coerced to syntax, use cx as lexctx and src 253 pr, es are progress and expectstack, respectively 254 rest-x, rest-cx, rest-pr are variable names to bind in context of success-expr 255 256 (stxclass-parser x cx pr es undos fail-handler cut-prompt role success-proc arg ...) : Ans 257 258 success-proc: 259 for stxclass, is (fail-handler undos attr-value ... -> Ans) 260 for splicing-stxclass, is (undos fail-handler rest-x rest-cx rest-pr attr-value -> Ans) 261 fail-handler, cut-prompt : undos failure -> Ans 262 263 Fail-handler is normally represented with stxparam 'fail-handler', but must be 264 threaded through stxclass calls (in through stxclass-parser, out through 265 success-proc) to support backtracking. Cut-prompt is never changed within 266 stxclass or within alternative, so no threading needed. 267 268 The undo stack is normally represented with stxparam 'undo-stack', but must be 269 threaded through stxclass calls (like fail-handler). A failure handler closes 270 over a base undo stack and receives an extended current undo stack; the failure 271 handler unwinds effects by performing every action in the difference between 272 them and then restores the saved undo stack. 273 274 Usually sub-patterns processed in tail position, but *can* do non-tail calls for: 275 - ~commit 276 - var of stxclass with ~commit 277 It is also safe to keep normal tail-call protocol and just adjust fail-handler. 278 There is no real benefit to specializing ~commit, since it does not involve 279 creating a success closure. 280 281 Some optimizations: 282 - commit protocol for stxclasses (but not ~commit, no point) 283 - avoid continue-vs-end choice point in (EH ... . ()) by eager pair check 284 - integrable stxclasses, specialize ellipses of integrable stxclasses 285 - pattern lists that cannot fail set es=#f to disable ExpectStack allocation 286 |# 287 288 ;; ---- 289 290 (begin-for-syntax 291 (define (wash stx) 292 (syntax-e stx)) 293 (define (wash-list washer stx) 294 (let ([l (stx->list stx)]) 295 (unless l (raise-type-error 'wash-list "stx-list" stx)) 296 (map washer l))) 297 (define (wash-iattr stx) 298 (with-syntax ([#s(attr name depth syntax?) stx]) 299 (attr #'name (wash #'depth) (wash #'syntax?)))) 300 (define (wash-sattr stx) 301 (with-syntax ([#s(attr name depth syntax?) stx]) 302 (attr (wash #'name) (wash #'depth) (wash #'syntax?)))) 303 (define (wash-iattrs stx) 304 (wash-list wash-iattr stx)) 305 (define (wash-sattrs stx) 306 (wash-list wash-sattr stx)) 307 (define (generate-n-temporaries n) 308 (generate-temporaries 309 (for/list ([i (in-range n)]) 310 (string->symbol (format "g~sx" i)))))) 311 312 ;; ---- 313 314 #| 315 Conventions: 316 - rhs : RHS 317 - iattr : IAttr 318 - relsattr : SAttr 319 - splicing? : bool 320 - x : id (var) 321 - cx : id (var, may be shadowed) 322 - pr : id (var, may be shadowed) 323 - es : id (var, may be shadowed) 324 - success : var (bound to success procedure) 325 - k : expr 326 - rest-x, rest-cx, rest-pr : id (to be bound) 327 - fh, cp, rl : id (var) 328 |# 329 330 (begin-for-syntax 331 (define (rewrite-formals fstx x-id rl-id) 332 (with-syntax ([x x-id] 333 [rl rl-id]) 334 (let loop ([fstx fstx]) 335 (syntax-case fstx () 336 [([kw arg default] . more) 337 (keyword? (syntax-e #'kw)) 338 (cons #'(kw arg (with ([this-syntax x] [this-role rl]) default)) 339 (loop #'more))] 340 [([arg default] . more) 341 (not (keyword? (syntax-e #'kw))) 342 (cons #'(arg (with ([this-syntax x] [this-role rl]) default)) 343 (loop #'more))] 344 [(formal . more) 345 (cons #'formal (loop #'more))] 346 [_ fstx]))))) 347 348 ;; (with-maybe-delimit-cut bool expr) 349 (define-syntax with-maybe-delimit-cut 350 (syntax-rules () 351 [(wmdc #t k) 352 (with ([cut-prompt fail-handler]) k)] 353 [(wmdc #f k) 354 k])) 355 356 ;; (variant-success relsattrs variant (also:id ...) success bool) : expr[Ans] 357 (define-syntax (variant-success stx) 358 (syntax-case stx () 359 [(variant-success relsattrs iattrs (also ...) success cp0 commit?) 360 #`(with-maybe-reset-fail commit? cp0 361 (base-success-expr iattrs relsattrs (also ...) success))])) 362 363 ;; (with-maybe-reset-fail bool id expr) 364 (define-syntax with-maybe-reset-fail 365 (syntax-rules () 366 [(wmrs #t cp0 k) 367 (with ([fail-handler cp0]) k)] 368 [(wmrs #f cp0 k) 369 k])) 370 371 ;; (base-success-expr iattrs relsattrs (also:id ...) success) : expr[Ans] 372 (define-syntax (base-success-expr stx) 373 (syntax-case stx () 374 [(base-success-expr iattrs relsattrs (also ...) success) 375 (let ([reliattrs 376 (reorder-iattrs (wash-sattrs #'relsattrs) 377 (wash-iattrs #'iattrs))]) 378 (with-syntax ([(#s(attr name _ _) ...) reliattrs]) 379 #'(success fail-handler undo-stack also ... (attribute name) ...)))])) 380 381 ;; ---- 382 383 ;; (parse:clauses x clauses ctx) 384 (define-syntax (parse:clauses stx) 385 (syntax-case stx () 386 [(parse:clauses x clauses body-mode ctx) 387 ;; if templates? is true, expect one form after kwargs in clause, wrap it with syntax 388 ;; otherwise, expect non-empty body sequence (defs and exprs) 389 (with-disappeared-uses 390 (with-txlifts 391 (lambda () 392 (define who 393 (syntax-case #'ctx () 394 [(m . _) (identifier? #'m) #'m] 395 [_ 'syntax-parse])) 396 (define-values (chunks clauses-stx) 397 (parse-keyword-options #'clauses parse-directive-table 398 #:context #'ctx 399 #:no-duplicates? #t)) 400 (define context 401 (options-select-value chunks '#:context #:default #'x)) 402 (define colon-notation? 403 (not (assq '#:disable-colon-notation chunks))) 404 (define-values (decls0 defs) 405 (get-decls+defs chunks #t #:context #'ctx)) 406 ;; for-clause : stx -> (values pattern stx (listof stx)) 407 (define (for-clause clause) 408 (syntax-case clause () 409 [[p . rest] 410 (let-values ([(rest pattern defs2) 411 (parameterize ((stxclass-colon-notation? colon-notation?)) 412 (parse-pattern+sides #'p #'rest 413 #:splicing? #f 414 #:decls decls0 415 #:context #'ctx))]) 416 (let ([body-expr 417 (case (syntax-e #'body-mode) 418 ((one-template) 419 (syntax-case rest () 420 [(template) 421 #'(syntax template)] 422 [_ (raise-syntax-error #f "expected exactly one template" #'ctx)])) 423 ((body-sequence) 424 (syntax-case rest () 425 [(e0 e ...) 426 ;; Should we use a shadower (works on the whole file, unhygienically), 427 ;; or use the context of the syntax-parse identifier? 428 (let ([the-#%intdef-begin (datum->syntax #'ctx '#%intdef-begin)]) 429 (if (syntax-local-value the-#%intdef-begin (λ () #f)) ;; Defined as a macro 430 #`(let () (#,the-#%intdef-begin e0 e ...)) 431 #'(let () e0 e ...)))] 432 [_ (raise-syntax-error #f "expected non-empty clause body" 433 #'ctx clause)])) 434 (else 435 (raise-syntax-error #f "internal error: unknown body mode" #'ctx #'body-mode)))]) 436 (values pattern body-expr defs2)))] 437 [_ (raise-syntax-error #f "expected clause" #'ctx clause)])) 438 (unless (stx-list? clauses-stx) 439 (raise-syntax-error #f "expected sequence of clauses" #'ctx)) 440 (define-values (patterns body-exprs defs2s) 441 (for/lists (patterns body-exprs defs2s) ([clause (in-list (stx->list clauses-stx))]) 442 (for-clause clause))) 443 (define no-fail? (patterns-cannot-fail? patterns)) 444 (when no-fail? (log-syntax-parse-debug "cannot fail: ~e" #'ctx)) 445 (with-syntax ([(def ...) (apply append (get-txlifts-as-definitions) defs defs2s)]) 446 #`(let* ([ctx0 (normalize-context '#,who #,context x)] 447 [pr (ps-empty x (cadr ctx0))] 448 [es #,(if no-fail? #'#f #'#t)] 449 [cx x] 450 [fh0 (syntax-patterns-fail ctx0)]) 451 def ... 452 (parameterize ((current-syntax-context (cadr ctx0)) 453 (current-state '#hasheq()) 454 (current-state-writable? #f)) 455 (with ([fail-handler fh0] 456 [cut-prompt fh0] 457 [undo-stack null]) 458 #,(cond [(pair? patterns) 459 (with-syntax ([matrix 460 (optimize-matrix 461 (for/list ([pattern (in-list patterns)] 462 [body-expr (in-list body-exprs)]) 463 (pk1 (list pattern) body-expr)))]) 464 #'(parse:matrix ((x cx pr es)) matrix)) 465 #| 466 (with-syntax ([(alternative ...) 467 (for/list ([pattern (in-list patterns)] 468 [body-expr (in-list body-exprs)]) 469 #`(parse:S x cx #,pattern pr es #,body-expr))]) 470 #`(try alternative ...)) 471 |#] 472 [else 473 #`(fail (failure* pr es))]))))))))])) 474 475 ;; ---- 476 477 ;; (parse:matrix ((x cx pr es) ...) (PK ...)) : expr[Ans] 478 ;; (parse:matrix (in1 ... inN) (#s(pk1 (P11 ... P1N) e1) ... #s(pk1 (PM1 ... PMN) eM))) 479 ;; represents the matching matrix 480 ;; [_in1_..._inN_|____] 481 ;; [ P11 ... P1N | e1 ] 482 ;; [ ⋮ ⋮ | ⋮ ] 483 ;; [ PM1 ... PMN | eM ] 484 485 (define-syntax (parse:matrix stx) 486 (syntax-case stx () 487 [(parse:matrix ins (pk ...)) 488 #'(try (parse:pk ins pk) ...)])) 489 490 (define-syntax (parse:pk stx) 491 (syntax-case stx () 492 [(parse:pk () #s(pk1 () k)) 493 #'k] 494 [(parse:pk ((x cx pr es) . ins) #s(pk1 (pat1 . pats) k)) 495 #'(parse:S x cx pat1 pr es (parse:pk ins #s(pk1 pats k)))] 496 [(parse:pk ((x cx pr es) . ins) #s(pk/same pat1 inner)) 497 #'(parse:S x cx pat1 pr es (parse:matrix ins inner))] 498 [(parse:pk ((x cx pr es) . ins) #s(pk/pair inner)) 499 #'(let-values ([(datum tcx) 500 (if (syntax? x) 501 (values (syntax-e x) x) 502 (values x cx))]) 503 (if (pair? datum) 504 (let ([hx (car datum)] 505 [hcx (car datum)] 506 [hpr (ps-add-car pr)] 507 [tx (cdr datum)] 508 [tpr (ps-add-cdr pr)]) 509 (parse:matrix ((hx hcx hpr es) (tx tcx tpr es) . ins) inner)) 510 (let ([es* (if (null? datum) (es-add-proper-pair (first-desc:matrix inner) es) es)]) 511 (fail (failure* pr es*)))))] 512 [(parse:pk (in1 . ins) #s(pk/and inner)) 513 #'(parse:matrix (in1 in1 . ins) inner)])) 514 515 (define-syntax (first-desc:matrix stx) 516 (syntax-case stx () 517 [(fdm (#s(pk1 (pat1 . pats) k))) 518 #'(first-desc:S pat1)] 519 [(fdm (#s(pk/same pat1 pks))) 520 #'(first-desc:S pat1)] 521 [(fdm (pk ...)) ;; FIXME 522 #'#f])) 523 524 ;; ---- 525 526 ;; (parse:S x cx S-pattern pr es k) : expr[Ans] 527 ;; In k: attrs(S-pattern) are bound. 528 (define-syntax (parse:S stx) 529 (syntax-case stx () 530 [(parse:S x cx pattern0 pr es k) 531 (syntax-case #'pattern0 () 532 [#s(internal-rest-pattern rest-x rest-cx rest-pr) 533 #`(let ([rest-x x] 534 [rest-cx cx] 535 [rest-pr pr]) 536 k)] 537 [#s(pat:any) 538 #'k] 539 [#s(pat:svar name) 540 #'(let-attributes ([#s(attr name 0 #t) (datum->syntax cx x cx)]) 541 k)] 542 [#s(pat:var/p name parser argu (nested-a ...) role 543 #s(scopts attr-count commit? _delimit? _desc)) 544 (with-syntax ([(av ...) (generate-n-temporaries (syntax-e #'attr-count))] 545 [(name-attr ...) 546 (if (identifier? #'name) 547 #'([#s(attr name 0 #t) (datum->syntax cx x cx)]) 548 #'())]) 549 (if (not (syntax-e #'commit?)) 550 ;; The normal protocol 551 #'(app-argu parser x cx pr es undo-stack fail-handler cut-prompt role 552 (lambda (fh undos av ...) 553 (let-attributes (name-attr ...) 554 (let-attributes* ((nested-a ...) (av ...)) 555 (with ([fail-handler fh] [undo-stack undos]) 556 k)))) 557 argu) 558 ;; The commit protocol 559 ;; (Avoids putting k in procedure) 560 #'(let-values ([(fs undos av ...) 561 (with ([fail-handler 562 (lambda (undos fs) 563 (unwind-to undos undo-stack) 564 (values fs undo-stack (let ([av #f]) av) ...))]) 565 (with ([cut-prompt fail-handler]) 566 (app-argu parser x cx pr es undo-stack 567 fail-handler cut-prompt role 568 (lambda (fh undos av ...) (values #f undos av ...)) 569 argu)))]) 570 (if fs 571 (fail fs) 572 (let-attributes (name-attr ...) 573 (let-attributes* ((nested-a ...) (av ...)) 574 (with ([undo-stack undos]) 575 k)))))))] 576 [#s(pat:reflect obj argu attr-decls name (nested-a ...)) 577 (with-syntax ([(name-attr ...) 578 (if (identifier? #'name) 579 #'([#s(attr name 0 #t) (datum->syntax cx x cx)]) 580 #'())]) 581 (with-syntax ([arity (arguments->arity (syntax->datum #'argu))]) 582 #'(let ([parser (reflect-parser obj 'arity 'attr-decls #f)]) 583 (app-argu parser x cx pr es undo-stack fail-handler cut-prompt #f 584 (lambda (fh undos . result) 585 (let-attributes (name-attr ...) 586 (let/unpack ((nested-a ...) result) 587 (with ([fail-handler fh] [undo-stack undos]) 588 k)))) 589 argu))))] 590 [#s(pat:datum datum) 591 (with-syntax ([unwrap-x 592 (if (atomic-datum-stx? #'datum) 593 #'(if (syntax? x) (syntax-e x) x) 594 #'(syntax->datum (datum->syntax #f x)))]) 595 #`(let ([d unwrap-x]) 596 (if (equal? d (quote datum)) 597 k 598 (fail (failure* pr (es-add-atom 'datum es))))))] 599 [#s(pat:literal literal input-phase lit-phase) 600 #`(if (and (identifier? x) 601 (free-identifier=? x (quote-syntax literal) input-phase lit-phase)) 602 (with ([undo-stack (cons (current-state) undo-stack)]) 603 (state-cons! 'literals x) 604 k) 605 (fail (failure* pr (es-add-literal (quote-syntax literal) es))))] 606 [#s(pat:action action subpattern) 607 #'(parse:A x cx action pr es (parse:S x cx subpattern pr es k))] 608 [#s(pat:head head tail) 609 #`(parse:H x cx rest-x rest-cx rest-pr head pr es 610 (parse:S rest-x rest-cx tail rest-pr es k))] 611 [#s(pat:dots head tail) 612 #`(parse:dots x cx head tail pr es k)] 613 [#s(pat:and subpatterns) 614 (for/fold ([k #'k]) ([subpattern (in-list (reverse (syntax->list #'subpatterns)))]) 615 #`(parse:S x cx #,subpattern pr es #,k))] 616 [#s(pat:or (a ...) (subpattern ...) (subattrs ...)) 617 (with-syntax ([(#s(attr id _ _) ...) #'(a ...)]) 618 #`(let ([success 619 (lambda (fh undos id ...) 620 (let-attributes ([a id] ...) 621 (with ([fail-handler fh] [undo-stack undos]) 622 k)))]) 623 (try (parse:S x cx subpattern pr es 624 (disjunct subattrs success () (id ...))) 625 ...)))] 626 [#s(pat:not subpattern) 627 #`(let* ([fh0 fail-handler] 628 [pr0 pr] 629 [es0 es] 630 [fail-to-succeed 631 (lambda (undos fs) (unwind-to undos undo-stack) k)]) 632 ;; ~not implicitly prompts to be safe, 633 ;; but ~! not allowed within ~not (unless within ~delimit-cut, etc) 634 ;; (statically checked!) 635 (with ([fail-handler fail-to-succeed] 636 [cut-prompt fail-to-succeed]) ;; to be safe 637 (parse:S x cx subpattern pr es 638 (fh0 undo-stack (failure* pr0 es0)))))] 639 [#s(pat:pair head tail) 640 #`(let ([datum (if (syntax? x) (syntax-e x) x)] 641 [cx (if (syntax? x) x cx)]) ;; FIXME: shadowing cx?! 642 (if (pair? datum) 643 (let ([hx (car datum)] 644 [hcx (car datum)] 645 [hpr (ps-add-car pr)] 646 [tx (cdr datum)] 647 [tpr (ps-add-cdr pr)]) 648 (parse:S hx hcx head hpr es 649 (parse:S tx cx tail tpr es k))) 650 (let ([es* (if (null? datum) (es-add-proper-pair (first-desc:S head) es) es)]) 651 (fail (failure* pr es*)))))] 652 [#s(pat:vector subpattern) 653 #`(let ([datum (if (syntax? x) (syntax-e x) x)]) 654 (if (vector? datum) 655 (let ([datum (vector->list datum)] 656 [vcx (if (syntax? x) x cx)] ;; FIXME: (vector? datum) => (syntax? x) ??? 657 [pr* (ps-add-unvector pr)]) 658 (parse:S datum vcx subpattern pr* es k)) 659 (fail (failure* pr es))))] 660 [#s(pat:box subpattern) 661 #`(let ([datum (if (syntax? x) (syntax-e x) x)]) 662 (if (box? datum) 663 (let ([datum (unbox datum)] 664 [bcx (if (syntax? x) x cx)] ;; FIXME: (box? datum) => (syntax? x) ??? 665 [pr* (ps-add-unbox pr)]) 666 (parse:S datum bcx subpattern pr* es k)) 667 (fail (failure* pr es))))] 668 [#s(pat:pstruct key subpattern) 669 #`(let ([datum (if (syntax? x) (syntax-e x) x)]) 670 (if (let ([xkey (prefab-struct-key datum)]) 671 (and xkey (equal? xkey 'key))) 672 (let ([datum (cdr (vector->list (struct->vector datum)))] 673 [scx (if (syntax? x) x cx)] ;; FIXME: (struct? datum) => (syntax? x) ??? 674 [pr* (ps-add-unpstruct pr)]) 675 (parse:S datum scx subpattern pr* es k)) 676 (fail (failure* pr es))))] 677 [#s(pat:describe pattern description transparent? role) 678 #`(let ([es* (es-add-thing pr description transparent? role es)] 679 [pr* (if 'transparent? pr (ps-add-opaque pr))]) 680 (parse:S x cx pattern pr* es* k))] 681 [#s(pat:delimit pattern) 682 #`(let ([cp0 cut-prompt]) 683 (with ([cut-prompt fail-handler]) 684 (parse:S x cx pattern pr es (with ([cut-prompt cp0]) k))))] 685 [#s(pat:commit pattern) 686 #`(let ([fh0 fail-handler] 687 [cp0 cut-prompt]) 688 (with ([cut-prompt fh0]) 689 (parse:S x cx pattern pr es 690 (with ([cut-prompt cp0] 691 [fail-handler fh0]) 692 k))))] 693 [#s(pat:ord pattern group index) 694 #`(let ([pr* (ps-add pr '#s(ord group index))]) 695 (parse:S x cx pattern pr* es k))] 696 [#s(pat:post pattern) 697 #`(let ([pr* (ps-add-post pr)]) 698 (parse:S x cx pattern pr* es k))] 699 [#s(pat:integrated name predicate description role) 700 (with-syntax ([(name-attr ...) 701 (if (identifier? #'name) 702 #'([#s(attr name 0 #t) x*]) 703 #'())]) 704 #'(let ([x* (datum->syntax cx x cx)]) 705 (if (predicate x*) 706 (let-attributes (name-attr ...) k) 707 (let ([es* (es-add-thing pr 'description #t role es)]) 708 (fail (failure* pr es*))))))])])) 709 710 ;; (first-desc:S S-pattern) : expr[FirstDesc] 711 (define-syntax (first-desc:S stx) 712 (syntax-case stx () 713 [(fds p) 714 (syntax-case #'p () 715 [#s(pat:any) 716 #''(any)] 717 [#s(pat:svar name) 718 #''(any)] 719 [#s(pat:var/p _ _ _ _ _ #s(scopts _ _ _ desc)) 720 #'(quote desc)] 721 [#s(pat:datum d) 722 #''(datum d)] 723 [#s(pat:literal id _ip _lp) 724 #''(literal id)] 725 [#s(pat:describe _p desc _t? _role) 726 #`(quote #,(or (constant-desc #'desc) #'#f))] 727 [#s(pat:delimit pattern) 728 #'(first-desc:S pattern)] 729 [#s(pat:commit pattern) 730 #'(first-desc:S pattern)] 731 [#s(pat:ord pattern _ _) 732 #'(first-desc:S pattern)] 733 [#s(pat:post pattern) 734 #'(first-desc:S pattern)] 735 [#s(pat:integrated _name _pred description _role) 736 #''description] 737 [_ #'#f])])) 738 739 ;; (first-desc:H HeadPattern) : Expr 740 (define-syntax (first-desc:H stx) 741 (syntax-case stx () 742 [(fdh hpat) 743 (syntax-case #'hpat () 744 [#s(hpat:var/p _ _ _ _ _ #s(scopts _ _ _ desc)) #'(quote desc)] 745 [#s(hpat:seq lp) #'(first-desc:L lp)] 746 [#s(hpat:describe _hp desc _t? _r) 747 #`(quote #,(or (constant-desc #'desc) #'#f))] 748 [#s(hpat:delimit hp) #'(first-desc:H hp)] 749 [#s(hpat:commit hp) #'(first-desc:H hp)] 750 [#s(hpat:ord hp _ _) #'(first-desc:H hp)] 751 [#s(hpat:post hp) #'(first-desc:H hp)] 752 [_ #'(first-desc:S hpat)])])) 753 754 (define-syntax (first-desc:L stx) 755 (syntax-case stx () 756 [(fdl lpat) 757 (syntax-case #'lpat () 758 [#s(pat:pair sp lp) #'(first-desc:S sp)] 759 [_ #'#f])])) 760 761 ;; (disjunct (iattr ...) success (pre:expr ...) (id:id ...)) : expr[Ans] 762 (define-syntax (disjunct stx) 763 (syntax-case stx () 764 [(disjunct (#s(attr sub-id _ _) ...) success (pre ...) (id ...)) 765 (with-syntax ([(alt-sub-id ...) (generate-temporaries #'(sub-id ...))]) 766 #`(let ([alt-sub-id (attribute sub-id)] ...) 767 (let ([id #f] ...) 768 (let ([sub-id alt-sub-id] ...) 769 (success fail-handler undo-stack pre ... id ...)))))])) 770 771 ;; (parse:A x cx A-pattern pr es k) : expr[Ans] 772 ;; In k: attrs(A-pattern) are bound. 773 (define-syntax (parse:A stx) 774 (syntax-case stx () 775 [(parse:A x cx pattern0 pr es k) 776 (syntax-case #'pattern0 () 777 [#s(action:and (action ...)) 778 (for/fold ([k #'k]) ([action (in-list (reverse (syntax->list #'(action ...))))]) 779 #`(parse:A x cx #,action pr es #,k))] 780 [#s(action:cut) 781 #'(with ([fail-handler cut-prompt]) k)] 782 [#s(action:bind a expr) 783 #'(let-attributes ([a (wrap-user-code expr)]) k)] 784 [#s(action:fail condition message) 785 #`(let ([c (wrap-user-code condition)]) 786 (if c 787 (let ([pr* (if (syntax? c) (ps-add-stx pr c) pr)] 788 [es* (es-add-message message es)]) 789 (fail (failure* pr* es*))) 790 k))] 791 [#s(action:parse pattern expr) 792 #`(let* ([y (datum->syntax/with-clause (wrap-user-code expr))] 793 [cy y] 794 [pr* (ps-add-stx pr y)]) 795 (parse:S y cy pattern pr* es k))] 796 [#s(action:do (stmt ...)) 797 #'(parameterize ((current-state-writable? #t)) 798 (let ([init-state (current-state)]) 799 (no-shadow stmt) ... 800 (parameterize ((current-state-writable? #f)) 801 (with ([undo-stack (maybe-add-state-undo init-state (current-state) undo-stack)]) 802 (#%expression k)))))] 803 [#s(action:undo (stmt ...)) 804 #'(with ([undo-stack (cons (lambda () stmt ... (void)) undo-stack)] 805 [cut-prompt illegal-cut-error]) 806 k)] 807 [#s(action:ord pattern group index) 808 #'(let ([pr* (ps-add pr '#s(ord group index))]) 809 (parse:A x cx pattern pr* es k))] 810 [#s(action:post pattern) 811 #'(let ([pr* (ps-add-post pr)]) 812 (parse:A x cx pattern pr* es k))])])) 813 814 (begin-for-syntax 815 ;; convert-list-pattern : ListPattern id -> SinglePattern 816 ;; Converts '() datum pattern at end of list to bind (cons stx index) 817 ;; to rest-var. 818 (define (convert-list-pattern pattern end-pattern) 819 (syntax-case pattern () 820 [#s(pat:datum ()) 821 end-pattern] 822 [#s(pat:action action tail) 823 (with-syntax ([tail (convert-list-pattern #'tail end-pattern)]) 824 #'#s(pat:action action tail))] 825 [#s(pat:head head tail) 826 (with-syntax ([tail (convert-list-pattern #'tail end-pattern)]) 827 #'#s(pat:head head tail))] 828 [#s(pat:dots head tail) 829 (with-syntax ([tail (convert-list-pattern #'tail end-pattern)]) 830 #'#s(pat:dots head tail))] 831 [#s(pat:pair head-part tail-part) 832 (with-syntax ([tail-part (convert-list-pattern #'tail-part end-pattern)]) 833 #'#s(pat:pair head-part tail-part))]))) 834 835 ;; (parse:H x cx rest-x rest-cx rest-pr H-pattern pr es k) 836 ;; In k: rest, rest-pr, attrs(H-pattern) are bound. 837 (define-syntax (parse:H stx) 838 (syntax-case stx () 839 [(parse:H x cx rest-x rest-cx rest-pr head pr es k) 840 (syntax-case #'head () 841 [#s(hpat:describe pattern description transparent? role) 842 #`(let ([es* (es-add-thing pr description transparent? role es)] 843 [pr* (if 'transparent? pr (ps-add-opaque pr))]) 844 (parse:H x cx rest-x rest-cx rest-pr pattern pr* es* 845 (let ([rest-pr (if 'transparent? rest-pr (ps-pop-opaque rest-pr))]) 846 k)))] 847 [#s(hpat:var/p name parser argu (nested-a ...) role 848 #s(scopts attr-count commit? _delimit? _desc)) 849 (with-syntax ([(av ...) (generate-n-temporaries (syntax-e #'attr-count))] 850 [(name-attr ...) 851 (if (identifier? #'name) 852 #'([#s(attr name 0 #t) 853 (stx-list-take x (ps-difference pr rest-pr))]) 854 #'())]) 855 (if (not (syntax-e #'commit?)) 856 ;; The normal protocol 857 #`(app-argu parser x cx pr es undo-stack fail-handler cut-prompt role 858 (lambda (fh undos rest-x rest-cx rest-pr av ...) 859 (let-attributes (name-attr ...) 860 (let-attributes* ((nested-a ...) (av ...)) 861 (with ([fail-handler fh] [undo-stack undos]) 862 k)))) 863 argu) 864 ;; The commit protocol 865 ;; (Avoids putting k in procedure) 866 #'(let-values ([(fs undos rest-x rest-cx rest-pr av ...) 867 (with ([fail-handler 868 (lambda (undos fs) 869 (unwind-to undos undo-stack) 870 (values fs undo-stack #f #f #f (let ([av #f]) av) ...))]) 871 (with ([cut-prompt fail-handler]) 872 (app-argu parser x cx pr es undo-stack 873 fail-handler cut-prompt role 874 (lambda (fh undos rest-x rest-cx rest-pr av ...) 875 (values #f undos rest-x rest-cx rest-pr av ...)) 876 argu)))]) 877 (if fs 878 (fail fs) 879 (let-attributes (name-attr ...) 880 (let-attributes* ((nested-a ...) (av ...)) 881 (with ([undo-stack undos]) 882 k)))))))] 883 [#s(hpat:reflect obj argu attr-decls name (nested-a ...)) 884 (with-syntax ([(name-attr ...) 885 (if (identifier? #'name) 886 #'([#s(attr name 0 #t) 887 (stx-list-take x (ps-difference pr rest-pr))]) 888 #'())]) 889 (with-syntax ([arity (arguments->arity (syntax->datum #'argu))]) 890 #'(let ([parser (reflect-parser obj 'arity 'attr-decls #t)]) 891 (app-argu parser x cx pr es undo-stack fail-handler cut-prompt #f 892 (lambda (fh undos rest-x rest-cx rest-pr . result) 893 (let-attributes (name-attr ...) 894 (let/unpack ((nested-a ...) result) 895 (with ([fail-handler fh] [undo-stack undos]) 896 k)))) 897 argu))))] 898 [#s(hpat:and head single) 899 #`(let ([cx0 cx]) 900 (parse:H x cx rest-x rest-cx rest-pr head pr es 901 (let ([lst (stx-list-take x (ps-difference pr rest-pr))]) 902 (parse:S lst cx0 single pr es k))))] 903 [#s(hpat:or (a ...) (subpattern ...) (subattrs ...)) 904 (with-syntax ([(#s(attr id _ _) ...) #'(a ...)]) 905 #`(let ([success 906 (lambda (fh undos rest-x rest-cx rest-pr id ...) 907 (let-attributes ([a id] ...) 908 (with ([fail-handler fh] [undo-stack undos]) 909 k)))]) 910 (try (parse:H x cx rest-x rest-cx rest-pr subpattern pr es 911 (disjunct subattrs success (rest-x rest-cx rest-pr) (id ...))) 912 ...)))] 913 [#s(hpat:seq pattern) 914 (with-syntax ([pattern 915 (convert-list-pattern 916 #'pattern 917 #'#s(internal-rest-pattern rest-x rest-cx rest-pr))]) 918 #'(parse:S x cx pattern pr es k))] 919 [#s(hpat:action action subpattern) 920 #'(parse:A x cx action pr es (parse:H x cx rest-x rest-cx rest-pr subpattern pr es k))] 921 [#s(hpat:delimit pattern) 922 #'(let ([cp0 cut-prompt]) 923 (with ([cut-prompt fail-handler]) 924 (parse:H x cx rest-x rest-cx rest-pr pattern pr es 925 (with ([cut-prompt cp0]) k))))] 926 [#s(hpat:commit pattern) 927 #`(let ([fh0 fail-handler] 928 [cp0 cut-prompt]) 929 (with ([cut-prompt fh0]) 930 (parse:H x cx rest-x rest-cx rest-pr pattern pr es 931 (with ([cut-prompt cp0] 932 [fail-handler fh0]) 933 k))))] 934 [#s(hpat:ord pattern group index) 935 #`(let ([pr* (ps-add pr '#s(ord group index))]) 936 (parse:H x cx rest-x rest-cx rest-pr pattern pr* es 937 (let ([rest-pr (ps-pop-ord rest-pr)]) k)))] 938 [#s(hpat:post pattern) 939 #'(let ([pr* (ps-add-post pr)]) 940 (parse:H x cx rest-x rest-cx rest-pr pattern pr* es 941 (let ([rest-pr (ps-pop-post rest-pr)]) k)))] 942 [#s(hpat:peek pattern) 943 #`(let ([saved-x x] [saved-cx cx] [saved-pr pr]) 944 (parse:H x cx dummy-x dummy-cx dummy-pr pattern pr es 945 (let ([rest-x saved-x] [rest-cx saved-cx] [rest-pr saved-pr]) 946 k)))] 947 [#s(hpat:peek-not subpattern) 948 #`(let* ([fh0 fail-handler] 949 [pr0 pr] 950 [es0 es] 951 [fail-to-succeed 952 (lambda (undos fs) 953 (unwind-to undos undo-stack) 954 (let ([rest-x x] 955 [rest-cx cx] 956 [rest-pr pr]) 957 k))]) 958 ;; ~not implicitly prompts to be safe, 959 ;; but ~! not allowed within ~not (unless within ~delimit-cut, etc) 960 ;; (statically checked!) 961 (with ([fail-handler fail-to-succeed] 962 [cut-prompt fail-to-succeed]) ;; to be safe 963 (parse:H x cx rest-x rest-cx rest-pr subpattern pr es 964 (fh0 undo-stack (failure* pr0 es0)))))] 965 [_ 966 #'(parse:S x cx 967 ;; FIXME: consider proper-list-pattern? (yes is consistent with ~seq) 968 #s(pat:pair head #s(internal-rest-pattern rest-x rest-cx rest-pr)) 969 pr es k)])])) 970 971 ;; (parse:dots x cx EH-pattern S-pattern pr es k) : expr[Ans] 972 ;; In k: attrs(EH-pattern, S-pattern) are bound. 973 (define-syntax (parse:dots stx) 974 (syntax-case stx () 975 ;; == Specialized cases 976 ;; -- (x ... . ()) 977 [(parse:dots x cx (#s(ehpat (attr0) #s(pat:svar name) #f #f)) 978 #s(pat:datum ()) pr es k) 979 #'(let-values ([(status result) (predicate-ellipsis-parser x cx pr es void #f #f)]) 980 (case status 981 ((ok) (let-attributes ([attr0 result]) k)) 982 (else (fail result))))] 983 ;; -- (x:sc ... . ()) where sc is an integrable stxclass like id or expr 984 [(parse:dots x cx (#s(ehpat (attr0) #s(pat:integrated _name pred? desc role) #f #f)) 985 #s(pat:datum ()) pr es k) 986 #'(let-values ([(status result) (predicate-ellipsis-parser x cx pr es pred? desc role)]) 987 (case status 988 ((ok) (let-attributes ([attr0 result]) k)) 989 (else (fail result))))] 990 ;; -- (x:sc ... . ()) where sc is a stxclass with commit 991 ;; Since head pattern does commit, no need to thread fail-handler, cut-prompt through. 992 ;; Microbenchmark suggests this isn't a useful specialization 993 ;; (probably try-or-pair/null-check already does the useful part) 994 ;; == General case 995 [(parse:dots x cx (#s(ehpat head-attrs head head-repc check-null?) ...) tail pr es k) 996 (let () 997 (define repcs (wash-list wash #'(head-repc ...))) 998 (define rep-ids (for/list ([repc (in-list repcs)]) 999 (and repc (generate-temporary 'rep)))) 1000 (define rel-repcs (filter values repcs)) 1001 (define rel-rep-ids (filter values rep-ids)) 1002 (define rel-heads (for/list ([head (in-list (syntax->list #'(head ...)))] 1003 [repc (in-list repcs)] 1004 #:when repc) 1005 head)) 1006 (define aattrs 1007 (for/list ([head-attrs (in-list (syntax->list #'(head-attrs ...)))] 1008 [repc (in-list repcs)] 1009 #:when #t 1010 [a (in-list (wash-iattrs head-attrs))]) 1011 (cons a repc))) 1012 (define attrs (map car aattrs)) 1013 (define attr-repcs (map cdr aattrs)) 1014 (define ids (map attr-name attrs)) 1015 (define tail-pattern-is-null? (equal? (syntax->datum #'tail) '#s(pat:datum ()))) 1016 (with-syntax ([(id ...) ids] 1017 [(alt-id ...) (generate-temporaries ids)] 1018 [reps rel-rep-ids] 1019 [(head-rep ...) rep-ids] 1020 [(rel-rep ...) rel-rep-ids] 1021 [(rel-repc ...) rel-repcs] 1022 [(rel-head ...) rel-heads] 1023 [(a ...) attrs] 1024 [(attr-repc ...) attr-repcs] 1025 [do-pair/null? 1026 ;; FIXME: do pair/null check only if no nullable head patterns 1027 ;; (and tail-pattern-is-null? (andmap not (syntax->datum #'(nullable? ...)))) 1028 tail-pattern-is-null?]) 1029 (define/with-syntax alt-map #'((id . alt-id) ...)) 1030 (define/with-syntax loop-k 1031 #'(dots-loop dx* dcx* loop-pr* undo-stack fail-handler rel-rep ... alt-id ...)) 1032 #`(let () 1033 ;; dots-loop : stx progress rel-rep ... alt-id ... -> Ans 1034 (define (dots-loop dx dcx loop-pr undos fh rel-rep ... alt-id ...) 1035 (with ([fail-handler fh] [undo-stack undos]) 1036 (try-or-pair/null-check do-pair/null? dx dcx loop-pr es 1037 (try (parse:EH dx dcx loop-pr head-attrs check-null? head-repc dx* dcx* loop-pr* 1038 alt-map head-rep head es loop-k) 1039 ...) 1040 (cond [(< rel-rep (rep:min-number rel-repc)) 1041 (let ([es (expectation-of-reps/too-few es rel-rep rel-repc rel-head)]) 1042 (fail (failure* loop-pr es)))] 1043 ... 1044 [else 1045 (let-attributes ([a (rep:finalize a attr-repc alt-id)] ...) 1046 (parse:S dx dcx tail loop-pr es k))])))) 1047 (let ([rel-rep 0] ... 1048 [alt-id (rep:initial-value attr-repc)] ...) 1049 (dots-loop x cx pr undo-stack fail-handler rel-rep ... alt-id ...)))))])) 1050 1051 ;; (try-or-pair/null-check bool x cx es pr pair-alt maybe-null-alt) 1052 (define-syntax try-or-pair/null-check 1053 (syntax-rules () 1054 [(topc #t x cx pr es pair-alt null-alt) 1055 (cond [(stx-pair? x) pair-alt] 1056 [(stx-null? x) null-alt] 1057 [else (fail (failure* pr es))])] 1058 [(topc _ x cx pr es alt1 alt2) 1059 (try alt1 alt2)])) 1060 1061 ;; (parse:EH x cx pr repc x* cx* pr* alts rep H-pattern es k) : expr[Ans] 1062 ;; In k: x*, cx*, pr*, alts`attrs(H-pattern) are bound and rep is shadowed. 1063 (define-syntax (parse:EH stx) 1064 (syntax-case stx () 1065 [(parse:EH x cx pr attrs check-null? repc x* cx* pr* alts rep head es k) 1066 (let () 1067 (define/with-syntax k* 1068 (let* ([main-attrs (wash-iattrs #'attrs)] 1069 [ids (map attr-name main-attrs)] 1070 [alt-ids 1071 (let ([table (make-bound-id-table)]) 1072 (for ([entry (in-list (syntax->list #'alts))]) 1073 (let ([entry (syntax-e entry)]) 1074 (bound-id-table-set! table (car entry) (cdr entry)))) 1075 (for/list ([id (in-list ids)]) (bound-id-table-ref table id)))]) 1076 (with-syntax ([(id ...) ids] 1077 [(alt-id ...) alt-ids]) 1078 #`(let ([alt-id (rep:combine repc (attribute id) alt-id)] ...) 1079 #,(if (syntax->datum #'check-null?) 1080 #'(if (zero? (ps-difference pr pr*)) (error/null-eh-match) k) 1081 #'k))))) 1082 (syntax-case #'repc () 1083 [#f #`(parse:H x cx x* cx* pr* head pr es k*)] 1084 [_ #`(parse:H x cx x* cx* pr* head pr es 1085 (if (< rep (rep:max-number repc)) 1086 (let ([rep (add1 rep)]) k*) 1087 (let ([es* (expectation-of-reps/too-many es rep repc)]) 1088 (fail (failure* pr* es*)))))]))])) 1089 1090 ;; (rep:initial-value RepConstraint) : expr 1091 (define-syntax (rep:initial-value stx) 1092 (syntax-case stx () 1093 [(_ #s(rep:once _ _ _)) #'#f] 1094 [(_ #s(rep:optional _ _ _)) #'#f] 1095 [(_ _) #'null])) 1096 1097 ;; (rep:finalize RepConstraint expr) : expr 1098 (define-syntax (rep:finalize stx) 1099 (syntax-case stx () 1100 [(_ a #s(rep:optional _ _ defaults) v) 1101 (with-syntax ([#s(attr name _ _) #'a] 1102 [(#s(action:bind da de) ...) #'defaults]) 1103 (let ([default 1104 (for/or ([da (in-list (syntax->list #'(da ...)))] 1105 [de (in-list (syntax->list #'(de ...)))]) 1106 (with-syntax ([#s(attr dname _ _) da]) 1107 (and (bound-identifier=? #'name #'dname) de)))]) 1108 (if default 1109 #`(or v #,default) 1110 #'v)))] 1111 [(_ a #s(rep:once _ _ _) v) #'v] 1112 [(_ a _ v) #'(reverse v)])) 1113 1114 ;; (rep:min-number RepConstraint) : expr 1115 (define-syntax (rep:min-number stx) 1116 (syntax-case stx () 1117 [(_ #s(rep:once _ _ _)) #'1] 1118 [(_ #s(rep:optional _ _ _)) #'0] 1119 [(_ #s(rep:bounds min max _ _ _)) #'min])) 1120 1121 ;; (rep:max-number RepConstraint) : expr 1122 (define-syntax (rep:max-number stx) 1123 (syntax-case stx () 1124 [(_ #s(rep:once _ _ _)) #'1] 1125 [(_ #s(rep:optional _ _ _)) #'1] 1126 [(_ #s(rep:bounds min max _ _ _)) #'max])) 1127 1128 ;; (rep:combine RepConstraint expr expr) : expr 1129 (define-syntax (rep:combine stx) 1130 (syntax-case stx () 1131 [(_ #s(rep:once _ _ _) a b) #'a] 1132 [(_ #s(rep:optional _ _ _) a b) #'a] 1133 [(_ _ a b) #'(cons a b)])) 1134 1135 ;; ---- 1136 1137 (define-syntax expectation-of-reps/too-few 1138 (syntax-rules () 1139 [(_ es rep #s(rep:once name too-few-msg too-many-msg) hpat) 1140 (cond [(or too-few-msg (name->too-few/once name)) 1141 => (lambda (msg) (es-add-message msg es))] 1142 [(first-desc:H hpat) => (lambda (fd) (es-add-proper-pair fd es))] 1143 [else es])] 1144 [(_ es rep #s(rep:optional name too-many-msg _) hpat) 1145 (error 'syntax-parse "INTERNAL ERROR: impossible (too-few)")] 1146 [(_ es rep #s(rep:bounds min max name too-few-msg too-many-msg) hpat) 1147 (cond [(or too-few-msg (name->too-few name)) 1148 => (lambda (msg) (es-add-message msg es))] 1149 [(first-desc:H hpat) => (lambda (fd) (es-add-proper-pair fd es))] 1150 [else es])])) 1151 1152 (define-syntax expectation-of-reps/too-many 1153 (syntax-rules () 1154 [(_ es rep #s(rep:once name too-few-msg too-many-msg)) 1155 (es-add-message (or too-many-msg (name->too-many name)) es)] 1156 [(_ es rep #s(rep:optional name too-many-msg _)) 1157 (es-add-message (or too-many-msg (name->too-many name)) es)] 1158 [(_ es rep #s(rep:bounds min max name too-few-msg too-many-msg)) 1159 (es-add-message (or too-many-msg (name->too-many name)) es)])) 1160 1161 ;; ==== 1162 1163 (define-syntax (define-eh-alternative-set stx) 1164 (define (parse-alt x) 1165 (syntax-case x (pattern) 1166 [(pattern alt) 1167 #'alt] 1168 [else 1169 (wrong-syntax x "expected eh-alternative-set alternative")])) 1170 (parameterize ((current-syntax-context stx)) 1171 (syntax-case stx () 1172 [(_ name a ...) 1173 (unless (identifier? #'name) 1174 (wrong-syntax #'name "expected identifier")) 1175 (let* ([alts (map parse-alt (syntax->list #'(a ...)))] 1176 [decls (new-declenv null #:conventions null)] 1177 [ehpat+hstx-list 1178 (apply append 1179 (for/list ([alt (in-list alts)]) 1180 (parse*-ellipsis-head-pattern alt decls #t #:context stx)))] 1181 [eh-alt+defs-list 1182 (for/list ([ehpat+hstx (in-list ehpat+hstx-list)]) 1183 (let ([ehpat (car ehpat+hstx)] 1184 [hstx (cadr ehpat+hstx)]) 1185 (cond [(syntax? hstx) 1186 (with-syntax ([(parser) (generate-temporaries '(eh-alt-parser))]) 1187 (let ([attrs (iattrs->sattrs (pattern-attrs (ehpat-head ehpat)))]) 1188 (list (eh-alternative (ehpat-repc ehpat) attrs #'parser) 1189 (list #`(define parser 1190 (parser/rhs parser () #,attrs 1191 [#:description #f (pattern #,hstx)] 1192 #t 1193 #,stx))))))] 1194 [(eh-alternative? hstx) 1195 (list hstx null)] 1196 [else 1197 (error 'define-eh-alternative-set "internal error: unexpected ~e" 1198 hstx)])))] 1199 [eh-alts (map car eh-alt+defs-list)] 1200 [defs (apply append (map cadr eh-alt+defs-list))]) 1201 (with-syntax ([(def ...) defs] 1202 [(alt-expr ...) 1203 (for/list ([alt (in-list eh-alts)]) 1204 (with-syntax ([repc-expr 1205 ;; repc structs are prefab; recreate using prefab 1206 ;; quasiquote exprs to avoid moving constructors 1207 ;; to residual module 1208 (syntax-case (eh-alternative-repc alt) () 1209 [#f 1210 #''#f] 1211 [#s(rep:once n u o) 1212 #'`#s(rep:once ,(quote-syntax n) 1213 ,(quote-syntax u) 1214 ,(quote-syntax o))] 1215 [#s(rep:optional n o d) 1216 #'`#s(rep:optional ,(quote-syntax n) 1217 ,(quote-syntax o) 1218 ,(quote-syntax d))] 1219 [#s(rep:bounds min max n u o) 1220 #'`#s(rep:bounds ,(quote min) 1221 ,(quote max) 1222 ,(quote-syntax n) 1223 ,(quote-syntax u) 1224 ,(quote-syntax o))])] 1225 [attrs-expr 1226 #`(quote #,(eh-alternative-attrs alt))] 1227 [parser-expr 1228 #`(quote-syntax #,(eh-alternative-parser alt))]) 1229 #'(eh-alternative repc-expr attrs-expr parser-expr)))]) 1230 #'(begin def ... 1231 (define-syntax name 1232 (eh-alternative-set (list alt-expr ...))))))])))