SHINMERA.s_LASS/compiler.lisp

306 lines
11 KiB
Common Lisp

#|
This file is a part of LASS
(c) 2014 Shirakumo http://tymoon.eu (shinmera@tymoon.eu)
Author: Nicolas Hafner <shinmera@tymoon.eu>
|#
(in-package #:org.tymoonnext.lass)
(defvar *vars* (make-hash-table)
"Special variable containing LASS-environment variables.
See the definition of the LET block.")
(defun read-to-vector (file)
(with-open-file (stream file :element-type '(unsigned-byte 8))
(let ((length (file-length stream)))
(assert length)
(let ((result (make-array length :element-type '(unsigned-byte 8))))
(read-sequence result stream)
result))))
(defgeneric resolve (thing)
(:documentation "Resolves THING to a value that makes sense for LASS.
By default the following types are handled:
NULL: NIL
STRING: the THING itself
ARRAY: the variable stored in *VARS* under THING
KEYWORD: Colon-prefixed, downcased symbol-name of THING
SYMBOL: Downcased symbol-name of THING
PATHNAME: If designating an image, base64 encoded inline image data.
T: PRINC-TO-STRING of THING")
(:method ((thing null))
NIL)
(:method ((thing string))
thing)
(:method ((thing array))
(gethash (aref thing 0) *vars*))
(:method ((thing symbol))
(if (keywordp thing)
(format NIL ":~a" (string-downcase thing))
(string-downcase thing)))
(:method ((file pathname))
(let ((type (mimes:mime-lookup file)))
(if (and (< 5 (length type))
(string= type "image" :end1 5))
(format NIL "url('data:~a;base64,~a')"
type (base64:usb8-array-to-base64-string
(read-to-vector file)))
(error "Don't know how to resolve files of type ~a" (or type file)))))
(:method ((thing T))
(princ-to-string thing)))
(defun make-property (property &optional value)
"Creates a property object with PROPERTY as its key and VALUE as its value."
(list :property property value))
(defun make-block (selector values)
"Creates a block object with SELECTOR and VALUES."
(list* :block (list* :selector selector) values))
(defun make-superblock (type selector blocks)
"Creates a block object that can contain other blocks, such as @media, etc."
(list* :superblock type (when selector (list* :selector selector)) blocks))
(defgeneric compile-property (key value)
(:documentation "Compile a property of KEY and VALUE to a list of property objects.
By default, the following cases are handled:
(T LIST)
A list is created with one property object, wherein the property-value is the
Space-concatenated list of RESOLVEd VALUEs. The KEY is DOWNCASEd.
(T T)
A list is created with one property object, wherein the property-value is the
RESOLVEd VALUE. The KEY is DOWNCASEd.
Special handling of properties may occur.
See DEFINE-SPECIAL-PROPERTY")
(:method (key (value list))
(list (make-property
(string-downcase key)
(format NIL "~{~a~^ ~}" (mapcar #'resolve value)))))
(:method (key value)
(list (make-property
(string-downcase key)
(resolve value)))))
;; THIS IS SOME PRETTY SHODDY MAGIC CODE HERE
;; BEWARE OF DRAGONS AND ALL THAT
;; YOU HAVE BEEN WARNED.
;;
;; Can't wait for bugs about this to hit me down the line.
(defgeneric compile-constraint (func args)
(:documentation "Compiles a constraint of type FUNC with arguments ARGS to a list of alternative selectors.
By default, the following cases are handled:
(T T)
Concatenates its ARGS together with spaces.
Preserves OR combinations.
(NULL NULL)
Returns NIL
(T NULL)
Returns FUNC
(:OR T)
Passes all ARGS to COMPILE-SELECTOR individually and then APPENDS
all the results together.
(:AND T)
Concatenates its ARGS together without spaces.
Preserves OR combinations.
Special handling of constraints may occur.
See DEFINE-SPECIAL-SELECTOR.")
(:method (func args)
(let ((cfunc (cond ((listp func)
(if (symbolp (first func))
(compile-selector func)
func))
(T (list (resolve func)))))
(cargs (compile-selector (car args))))
(loop with result = ()
for func in cfunc
do (loop for arg in cargs
do (push (list :constraint :combine " " func arg) result))
finally (return (compile-constraint (nreverse result) (cdr args))))))
(:method ((func null) (args null))
NIL)
(:method (func (args null))
func)
(:method ((func (eql :constraint)) args)
(list (list* func args)))
(:method ((func (eql :or)) args)
(apply #'append (mapcar #'compile-selector args)))
(:method ((func (eql :and)) args)
(when args
(if (cdr args)
(let ((cfunc (compile-selector (first args)))
(cargs (compile-selector (second args))))
(loop with result = ()
for func in cfunc
do (loop for arg in cargs
do (push (list :constraint :combine "" func arg) result))
finally (return (compile-constraint :and (cons (cons :OR (nreverse result)) (cddr args))))))
(if (and (listp (first args)) (eql (first (first args)) :OR))
(rest (first args))
args)))))
(defgeneric compile-selector (selector)
(:documentation "Compiles the SELECTOR form into a list of alternative selectors.
By default, the following cases are handled:
(NULL)
Returns NIL.
(LIST)
Calls COMPILE-CONSTRAINT with the SELECTOR's CAR and CDR.
(T)
Returns a list with the RESOLVEd SELECTOR.")
(:method ((selector null))
NIL)
(:method ((selector list))
(compile-constraint (car selector) (cdr selector)))
(:method ((selector T))
(list (list :constraint :literal (resolve selector)))))
(defgeneric compile-media-constraint (func args)
(:method (func args)
(loop for prop in (compile-property func args)
collect (list* :constraint prop)))
(:method ((func null) (args null))
NIL)
(:method (func (args null))
func)
(:method ((func (eql :constraint)) args)
(list (list* func args)))
(:method ((func (eql :property)) args)
(list (list* :constraint func args)))
(:method ((func (eql :or)) args)
(loop for arg in args
nconc (compile-media-query arg)))
(:method ((func (eql :and)) args)
(cond ((rest args)
(let ((cfunc (compile-media-query (first args)))
(cargs (compile-media-query (second args))))
(loop with result = ()
for func in cfunc
do (loop for arg in cargs
do (push (list :constraint :and func arg) result))
finally (return (compile-media-constraint :and (list* (list* :or (nreverse result))
(cddr args)))))))
(args
(compile-media-query (first args)))))
(:method ((func (eql :url)) args)
(list (list* :constraint :func "url" (mapcar #'resolve args))))
(:method ((func (eql :url-prefix)) args)
(list (list* :constraint :func "url-prefix" (mapcar #'resolve args))))
(:method ((func (eql :domain)) args)
(list (list* :constraint :func "domain" (mapcar #'resolve args))))
(:method ((func (eql :regexp)) args)
(list (list* :constraint :func "regexp" (mapcar #'resolve args)))))
(defgeneric compile-media-query (query)
(:method ((query null))
NIL)
(:method ((query list))
(compile-media-constraint (car query) (cdr query)))
(:method ((query T))
(list (list :constraint :literal (resolve query)))))
(defgeneric consume-item (item readable-list)
(:documentation "Consumes items from READABLE-LIST as required by the ITEM.
Returned should be two values, the first being a property to compile (or NIL)
and the second a block to compile (or NIL).
By default, the following cases are handled:
(LIST)
Simply returns the ITEM as a block.
(SYMBOL)
If it's a keyword, reads until the next keyword or list and returns that as a
property to compile. With property-functions, some sublists may also be read
in automatically. See DEFINE-PROPERTY-FUNCTION. If it is a regular symbol,
CALL-NEXT-METHOD is invoked.
(T)
Signals an error.")
(:method (thing readable-list)
(error "Don't know what to do with ~s (not part of a property)." thing))
(:method ((subblock list) readable-list)
(values
NIL
subblock))
(:method ((property symbol) readable-list)
(if (keywordp property)
(values
(let ((propvals ()))
(loop for (next fullp) = (multiple-value-list (peek readable-list))
while fullp
do (etypecase next
(keyword (return))
(list (return))
(T (push (consume readable-list) propvals))))
(cons property (nreverse propvals)))
NIL)
(call-next-method))))
(defgeneric compile-block (header fields)
(:documentation "Compiles the block with given HEADER and FIELDS list.
By default, the following case is handled:
(T T)
Blocks are handled in the following way:
The HEADER is used as a selector and compiled through COMPILE-SELECTOR.
Fields are semantically segregated through KEYWORDS and LISTS.
Every time a KEYWORD is encountered, it is taken as the current property
and all following objects until either a LIST or a KEYWORD is encountered
are gathered as the property's values.
Every time a LIST is encountered, it is taken as a SUB-BLOCK and is
passed to COMPILE-BLOCK with the HEADER being the current block's
selector prepended to the selector of the sub-block.
Special handling of blocks may occur.
See DEFINE-SPECIAL-BLOCK.")
(:method (selector fields)
(let ((selector (compile-selector selector))
(readable (make-readable-list fields))
(props ())
(blocks ()))
;; compute props and blocks
(flet ((add-prop (prop)
(when prop
(dolist (prop (compile-property (car prop) (cdr prop)))
(push prop props))))
(add-block (block)
(when block
(dolist (block (compile-block (list selector (car block)) (cdr block)))
(push block blocks)))))
(loop until (empty-p readable)
for (prop block) = (multiple-value-list (consume-item (consume readable) readable))
do (add-prop prop)
(add-block block)))
;; Returns list of blocks with ours consed to front
(cons (make-block selector (nreverse props))
(nreverse blocks)))))
(defun compile-sheet (&rest blocks)
"Compiles a LASS sheet composed of BLOCKS.
Each BLOCK is passed to COMPILE-BLOCK. The results thereof are appended
together into one list of blocks and properties."
(let ((sheet ()))
(dolist (block blocks)
(dolist (resulting-block (compile-block (car block) (cdr block)))
(push resulting-block sheet)))
(nreverse sheet)))