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|
;;; File: module-parser Author: John
;;; This is for using the parser to parse strings.
(define (parse-from-string string parse-proc filename)
(dynamic-let ((*current-file* filename))
(call-with-input-string string
(lambda (port)
(let ((tokens (lex-port port '#f)))
(init-token-stream tokens)
(let ((res (funcall parse-proc)))
(if (not (eq-token? 'eof))
(signal-leftover-tokens)
res)))))))
(define (signal-leftover-tokens)
(fatal-error 'leftover-tokens
"Leftover tokens after parsing."))
;;; This file deals with the basic structure of a module. It also adds
;;; the `module Main where' required by abbreviated modules.
(define (parse-tokens tokens)
(init-token-stream tokens)
(let ((mod (token-case
(|module| (parse-module))
(else (parse-modules/named '|Main| '())))))
(cons mod (parse-module-list))))
(define (parse-module)
(token-case
(modid (let* ((mod-name (token->symbol))
(exports (parse-exports)))
(require-token
|where|
(signal-missing-token "`where'" "module definition"))
(parse-modules/named mod-name exports)))
(else (signal-missing-token "<modid>" "module definition"))))
(define (parse-module-list)
(token-case
(|module|
(let ((mod (parse-module)))
(cons mod (parse-module-list))))
(eof '())
(else (signal-missing-module))))
(define (signal-missing-module)
(parser-error 'missing-module
"Missing `module', or leftover junk after module definition."))
(define (parse-exports)
(token-case
(\( (parse-export-list))
(else '())))
(define (parse-export-list)
(let ((entity (parse-entity 'export)))
(token-case
(\) (list entity))
(\, (cons entity (parse-export-list)))
(else (signal-missing-token "`)' or ','" "export list")))))
(define (parse-modules/named mod-name exports)
(trace-parser module
(let ((mod-ast (make module
(name mod-name)
(type 'standard)
(exports exports)
(default *standard-module-default*))))
(start-layout (lambda (in-layout?)
(parse-module-decls mod-ast in-layout? 'import))))))
;;; The mod-ast fields are kept in non-reversed order by appending
;;; each decl to the end of the appropriate list. This loses for
;;; value decls, so these are in reversed order!!
(define (parse-module-decls mod-ast in-layout? state)
(token-case
(|import| (let ((import (parse-import)))
(if (eq? state 'import)
(push-decl-list import (module-imports mod-ast))
(signal-misplaced-import)))
(terminate-topdecl mod-ast in-layout? state))
(|infix| (terminate-topdecl mod-ast in-layout?
(parse-fixity 'n mod-ast state)))
(|infixl| (terminate-topdecl mod-ast in-layout?
(parse-fixity 'l mod-ast state)))
(|infixr| (terminate-topdecl mod-ast in-layout?
(parse-fixity 'r mod-ast state)))
(|data| (let ((data-decl (parse-type-decl '#f)))
(push-decl-list data-decl (module-algdatas mod-ast)))
(terminate-topdecl mod-ast in-layout? 'topdecl))
(|type| (let ((synonym-decl (parse-synonym-decl)))
(push-decl-list synonym-decl (module-synonyms mod-ast)))
(terminate-topdecl mod-ast in-layout? 'topdecl))
(|class| (let ((class-decl (parse-class-decl)))
(push-decl-list class-decl (module-classes mod-ast)))
(terminate-topdecl mod-ast in-layout? 'topdecl))
(|instance| (let ((instance-decl (parse-instance-decl '#f)))
(push-decl-list instance-decl (module-instances mod-ast)))
(terminate-topdecl mod-ast in-layout? 'topdecl))
(|default| (let ((types
(token-case
(\( (token-case (\) '())
(else (parse-type-list))))
(else (list (parse-type))))))
(if (eq? (module-default mod-ast) *standard-module-default*)
(setf (module-default mod-ast)
(make default-decl (types types)))
(signal-multiple-defaults)))
(terminate-topdecl mod-ast in-layout? 'topdecl))
((begin-annotation no-advance)
(let ((annotations (parse-annotations)))
(setf (module-annotations mod-ast)
(append (module-annotations mod-ast) annotations)))
(terminate-topdecl mod-ast in-layout? state))
(pat-start (let ((decl (parse-decl)))
(setf (module-decls mod-ast)
(decl-push decl (module-decls mod-ast))))
(terminate-topdecl mod-ast in-layout? 'topdecl))
(else
(maybe-end-module mod-ast in-layout? state))))
(define (signal-misplaced-import)
(parser-error 'misplaced-import
"The import declaration is misplaced."))
(define (signal-multiple-defaults)
(parser-error 'multiple-defaults
"There are multiple default declarations."))
(define (terminate-topdecl mod-ast in-layout? state)
(token-case
(\; (parse-module-decls mod-ast in-layout? state))
(else (maybe-end-module mod-ast in-layout? state))))
(define (maybe-end-module mod-ast in-layout? state)
(declare (ignore state))
(cond ((or (eq-token? '|module|) (eq-token? 'eof) (eq-token? '\})
(eq-token? '$\}))
(close-layout in-layout?)
(wrapup-module mod-ast)
mod-ast)
(else
(signal-invalid-syntax "a topdecl"))))
(define (wrapup-module mod-ast)
(setf (module-decls mod-ast)
(nreverse (module-decls mod-ast)))
(when (and (null? (module-imports mod-ast))
(null? (module-decls mod-ast))
(null? (module-algdatas mod-ast))
(null? (module-synonyms mod-ast))
(null? (module-instances mod-ast))
(null? (module-classes mod-ast)))
(signal-empty-module)))
(define (signal-empty-module)
(parser-error 'empty-module "Module definition is empty."))
(define (parse-import)
(save-parser-context
(token-case
(modid (let ((mod (token->symbol))
(mode 'all)
(specs '()))
(token-case
(\( (setf mode 'by-name)
(token-case
(\) (setf specs '()))
(else (setf specs (parse-import-list)))))
(|hiding| (require-token
\(
(signal-missing-token "`('" "hiding clause"))
(setf specs (parse-import-list)))
(else '()))
(let ((renamings (token-case (|renaming|
(require-token
\(
(signal-missing-token
"`('" "renaming clause"))
(parse-renamings))
(else '()))))
(make import-decl (module-name mod) (mode mode) (specs specs)
(renamings renamings)))))
(else
(signal-missing-token "<modid>" "import declaration")))))
(define (parse-import-list)
(let ((import (parse-entity 'import)))
(token-case
(\, (cons import (parse-import-list)))
(\) (list import))
(else (signal-missing-token "`)' or `,'" "import list")))))
(define (parse-renamings)
(let ((renaming
(save-parser-context
(token-case
(var (let ((name1 (var->symbol)))
(require-token
|to|
(signal-missing-token "`to'" "import renaming clause"))
(token-case
(var (let ((name2 (var->symbol)))
(make renaming (from name1) (to name2)
(referenced? '#f))))
(else (signal-invalid-syntax "import renaming clause")))))
(con (let ((name1 (con->symbol)))
(require-token
|to|
(signal-missing-token "`to'" "import renaming clause"))
(token-case
(con (let ((name2 (con->symbol)))
(make renaming (from name1) (to name2)
(referenced? '#f))))
(else (signal-invalid-syntax "import renaming clause")))))
(else (signal-invalid-syntax "import renaming clause"))))))
(token-case (\, (cons renaming (parse-renamings)))
(\) (list renaming)))))
(define (parse-fixity associativity mod-ast state)
(let ((fixity-decl
(save-parser-context
(let* ((prec (token-case
(k (let ((p (token->integer)))
(cond ((<= p 9)
p)
(else
(signal-bad-fixity)
9))))
(else 9)))
(ops (parse-op-list))
(fixity (make fixity (associativity associativity)
(precedence prec))))
(make fixity-decl (fixity fixity) (names ops))))))
(push-decl-list fixity-decl (module-fixities mod-ast))
(cond ((or (eq? state 'import)
(eq? state 'fixity))
'fixity)
(else
(signal-misplaced-fixity)
state))))
(define (signal-bad-fixity)
(parser-error 'bad-fixity
"Expecting fixity value of 0 - 9."))
(define (signal-misplaced-fixity)
(parser-error 'misplaced-fixity "The fixity declaration is misplaced."))
(define (parse-op-list)
(let ((name (token-case
(op (op->symbol))
(else (signal-missing-token "<op>" "fixity declaration")))))
(token-case
(\, (cons name (parse-op-list)))
(else (list name)))))
(define (parse-entity context)
(trace-parser entity
(save-parser-context
(token-case
(var (var->entity))
(tycon
(let ((name (token->symbol)))
(token-case
(\( (token-case
(\.\. (require-token
'\)
(signal-missing-token "`)'" "class or datatype entity"))
(make entity-abbreviated (name name)))
(var (parse-entity-class name))
(con (parse-entity-datatype name))
(\) (make entity-class (name name) (methods '())))
(else (signal-invalid-syntax "an entity"))))
(\.\. (if (eq? context 'export)
(make entity-module (name name))
(signal-invalid-syntax "an entity")))
(else
(make entity-con (name name))))))
(else (signal-invalid-syntax "an entity"))))))
(define (parse-entity-class class-name)
(let ((vars (parse-var-list)))
(make entity-class (name class-name) (methods vars))))
(define (parse-entity-datatype type-name)
(let ((constrs (parse-con-list)))
(make entity-datatype (name type-name) (constructors constrs))))
(define (parse-var-list)
(token-case
(var (let ((name (var->symbol)))
(token-case
(\) (list name))
(\, (cons name (parse-var-list)))
(else
(signal-missing-token "`)' or `,'" "class entity")))))
(else (signal-missing-token "<var>" "class entity"))))
(define (parse-con-list)
(token-case
(con (let ((name (con->symbol)))
(token-case
(\) (list name))
(\, (cons name (parse-con-list)))
(else (signal-missing-token "`)' or `,'" "datatype entity")))))
(else (signal-missing-token "<con>" "datatype entity"))))
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