The reader Reference Manual

Table of Contents

The reader Reference Manual

This is the reader Reference Manual, version 0.10.0, generated automatically by Declt version 3.0 "Montgomery Scott" on Sun May 15 06:00:01 2022 GMT+0.

1 Introduction

Installation

Download from the Releases section.

I'll promote v0.10.0 to v1.0.0 if there are no significant changes over the next year.

Getting Started

(reader:enable-reader-syntax &rest reader-macro-identifiers)
;; OR
(reader+swank:enable-package-local-reader-syntax &rest reader-macro-identifiers)
;; (describe 'reader:enable-reader-syntax) ; for a list of identifiers

;; Complementory macros
;; (reader:disable-reader-syntax) ; is complementary
;; OR
;; (reader+swank-disable-package-local-reader-syntax)

Examples

CL-USER> #[[1 2 3
            4 5 6]
           [3 2 1
            7 8 9]]
#3A(((1 2 3) (4 5 6)) ((3 2 1) (7 8 9)))        ; cleaner syntax for arrays
CL-USER> (gethash 'a {eq 'a 1 'b 2})            ; hash-tables
1
T
CL-USER> (hash-set:hs-memberp #{"a" "b" "c"} "c") ; hash-set - can change in future
T
CL-USER> [#2A((1 2 3) (4 5 6)) 1 0]             ; accessors
4
CL-USER> (setf reader:*get-val-array-function* 'select:select)
SLCT:SELECT
CL-USER> (let ((arr #2A((1 2 3) (4 5 6))))
           [arr t 0])
#(1 4)
CL-USER> [{"a" 1 "b" 2} "a"]
1
T
CL-USER> [(cl-json:decode-json-from-string "{\"a\":1, \"b\":2}") :b] ; works with alists
2
CL-USER> (-> {"a" "apple" "b" "ball"} ["b"] [1]); accessors can be chained using arrows:->
#\a
CL-USER> #!echo -n hello world
hello world                                     ; Captures until the end of line
NIL                                             ; Should be possible to capture into a string
NIL                                             ; but not ideal for speed
0
CL-USER> (let ((a t)) !a)                       ; not
NIL
CL-USER> (let ((a 5.0d0)) $a)                   ; write-to-string
"5.0d0"                   ; should this be "ensure-string"? raise an issue!
CL-USER> ?reader:enable-reader-syntax           ; variable use not intended
READER:ENABLE-READER-SYNTAX
  [symbol]
ENABLE-READER-SYNTAX names a macro:
  Lambda-list: (&REST READER::READER-MACRO-IDENTIFIERS)
  Documentation:
    READER-MACRO-IDENTIFIERS are any of the following symbols:
      GET-VAL, HASH-TABLE, NOT, STRING, DESCRIBE, ARRAY, SET, RUN-PROGRAM
  Source file: /home/user/quicklisp/local-projects/reader/reader.lisp

Notes

The functions used for constructing arrays, hash-tables, sets, accessing array elements or accessors in general can be specified by

• *array-function*
• *hash-table-function*
• *set-function*
• *get-val-array-function*
• *get-val-function*

This should allow users to use fset or access or other libraries for the respective functions.

By default, alists and plists are treated distinct from lists whenever possible (see the get-val method specialized on lists). To disable this behavior, set each of these to T:

• *alists-are-lists*
• *plists-are-lists*

Hash Tables

• {"a" 1 "b" 2} - hash tables use 'equalp as the default test. The intended test function can be specified as the first element of the literal syntax. Besides providing with a choice, this also gets the indentation correct (see Modification for emacs.

Setting alists and plists

• (setf [] ...) does not work with empty alists and plists. This seems to require setf-expanders with get-val generic-function.

array vs get-val

• [...] (get-val) does not work inside #[...] (array) syntax. I do not have a plan or haven't figured out how to combine the two; and I find that okay since the array syntax is meant for cleaner representation in works involving matrices.

Notes for existing users upgrading to v0.10.0 from v0.9.1

Lambda

• lambda with the following usage has been removed.

CL-USER> (mapcar λ(write-to-string -) '(2 3 4)) ; lambdas
("2" "3" "4")

This begins to feel like line-noise after a while and is not ideal for readability; a better equivalent is the simple macro

CL-USER> (defmacro lm (&rest var-body)
           `(lambda ,(butlast var-body)
              ,@(last var-body)))
LM
CL-USER> (mapcar (lm o (write-to-string o)) '(2 3 4))
("2" "3" "4")

Hash-table

Since the function used for constructing hash-tables is now configurable (via reader:*hash-table-function*), the first input to the hash-table may be interpreted as the equality function. Thus, hash-table syntax can take an even (with default test cl:equalp) or odd (with the first symbol being interpreted as the equality function) number of arguments.

Setting alists and plists

Now works for non-empty lists.

Testing

(ql:quickload "reader")
(5am:run :reader)
;; OR
(asdf:test-system "reader")

Emacs Indentation Support

(modify-syntax-entry ?\[ "(]" lisp-mode-syntax-table)
(modify-syntax-entry ?\] ")[" lisp-mode-syntax-table)
(modify-syntax-entry ?\{ "(}" lisp-mode-syntax-table)
(modify-syntax-entry ?\} "){" lisp-mode-syntax-table)
(define-key paredit-mode-map (kbd "{") 'paredit-open-curly)
(define-key paredit-mode-map (kbd "}") 'paredit-close-curly)
(global-set-key (kbd "C-S-l") (lambda () ; for inserting lambda
                                (interactive)
                                (insert-char (aref (symbol-name 'λ) 0))))
(setq paredit-space-for-delimiter-predicates
      (list (lambda (endp delimiter)
              (not (and (eql ?\( delimiter)
                        (member (char-before (point))
                                '(?\@ ?λ))))))))
(set-language-environment "UTF-8")

Motivation: paredit curly brace matching in swank-clojure repl - Stack OverFlow

Known Issues

Known issues include aligning hash-tables without first-element-as-key:

{"hello" 1
         "world" 2}

A work-around is to specify the test as the first element, and let that default exist for one-liners:

{equal "hello" 1
       "world" 2}
{"hello" 1 "world" 2}

Comments

• cl-interpol is a prominent library providing perl / shell-like string interpolation facilities.
• cl-json can be used for parsing JSO

2 Systems

The main system appears first, followed by any subsystem dependency.

2.1 reader

Author

<Shubhamkar Ayare (shubhamayare@yahoo.co.in)>

License

MIT

Description

A utility library intended at providing configurable reader macros for
common tasks such as accessors, hash-tables, sets, uiop:run-program, arrays and a few others.

Version

0.10.0

Dependencies

• alexandria
• fiveam
• hash-set
• iterate
• split-sequence
• trivial-types
• uiop

Source

reader.asd (file)

Component

reader.lisp (file)

3 Files

Files are sorted by type and then listed depth-first from the systems components trees.

3.1 Lisp

3.1.1 reader.asd

Location

reader.asd

Systems

reader (system)

3.1.2 reader/reader.lisp

Parent

reader (system)

Location

reader.lisp

Packages

reader

Exported Definitions

• *alists-are-lists* (special variable)
• *array-function* (special variable)
• *get-val-array-function* (special variable)
• *get-val-function* (special variable)
• *hash-table-function* (special variable)
• *plists-are-lists* (special variable)
• *set-function* (special variable)
• disable-reader-syntax (macro)
• enable-reader-syntax (macro)
• get-val (generic function)
• get-val (method)
• (setf get-val) (method)
• get-val (method)
• (setf get-val) (method)
• get-val (method)
• (setf get-val) (method)
• get-val (method)
• (setf get-val) (method)
• get-val (method)
• (setf get-val) (method)
• (setf get-val) (method)

Internal Definitions

• %enable-reader-syntax (function)
• *previous-readtables* (special variable)
• *reader-macro-activation-functions* (special variable)
• +reader-macro-doc+ (constant)
• array-reader-macro (function)
• defmethods-with-setf (macro)
• describe-reader-macro (function)
• er (function)
• get-val-reader-macro (function)
• hash-table-reader-macro (function)
• list-to-hash-set-with-test (function)
• make-t-array-from-initial-contents (function)
• not-reader-macro (function)
• read-array (function)
• read-row-from-string (function)
• read-stream-as-string-until (function)
• read-stream-until (function)
• run-program-reader-macro (function)
• set-reader-macro (function)
• setp (macro)
• string-reader-macro (function)
• with-env (macro)
• with-reader-syntax (macro)

4 Packages

Packages are listed by definition order.

4.1 reader

Source

reader.lisp (file)

Use List

• split-sequence
• hash-set
• iterate
• common-lisp

Exported Definitions

• *alists-are-lists* (special variable)
• *array-function* (special variable)
• *get-val-array-function* (special variable)
• *get-val-function* (special variable)
• *hash-table-function* (special variable)
• *plists-are-lists* (special variable)
• *set-function* (special variable)
• disable-reader-syntax (macro)
• enable-reader-syntax (macro)
• get-val (generic function)
• get-val (method)
• (setf get-val) (method)
• get-val (method)
• (setf get-val) (method)
• get-val (method)
• (setf get-val) (method)
• get-val (method)
• (setf get-val) (method)
• get-val (method)
• (setf get-val) (method)
• (setf get-val) (generic function)
• (setf get-val) (method)

Internal Definitions

• %enable-reader-syntax (function)
• *previous-readtables* (special variable)
• *reader-macro-activation-functions* (special variable)
• +reader-macro-doc+ (constant)
• array-reader-macro (function)
• defmethods-with-setf (macro)
• describe-reader-macro (function)
• er (function)
• get-val-reader-macro (function)
• hash-table-reader-macro (function)
• list-to-hash-set-with-test (function)
• make-t-array-from-initial-contents (function)
• not-reader-macro (function)
• read-array (function)
• read-row-from-string (function)
• read-stream-as-string-until (function)
• read-stream-until (function)
• run-program-reader-macro (function)
• set-reader-macro (function)
• setp (macro)
• string-reader-macro (function)
• with-env (macro)
• with-reader-syntax (macro)

5 Definitions

Definitions are sorted by export status, category, package, and then by lexicographic order.

5.1 Exported definitions

5.1.1 Special variables

Special Variable: *alists-are-lists*

If T, ALISTS will not be treated specially by READER:GET-VAL method for lists.

Package

reader

Source

reader.lisp (file)

Special Variable: *array-function*

A symbol bound (at read-time) to a function that takes INITIAL-CONTENTS
as its argument and returns the array. INITIAL-CONTENTS is a list of nested-lists.

Package

reader

Source

reader.lisp (file)

Special Variable: *get-val-array-function*

A symbol bound (at read-time) to a function that takes
(ARRAY &REST SUBSCRIPTS)
as arguments and returns the corresponding value.
This is assumed to have a SETF defined.
This variable is significant if READER:*GET-VAL-FUNCTION* is bound to READER:GET-VAL.

Package

reader

Source

reader.lisp (file)

Special Variable: *get-val-function*

A symbol bound (at read-time) to a function that takes (OBJECT &REST KEY/S)
as arguments and returns the value corresponding to the KEY/S.

Package

reader

Source

reader.lisp (file)

Special Variable: *hash-table-function*

A symbol bound (at read-time) to a function that takes (PLIST &KEY TEST)
as arguments and returns the hash-table.

Package

reader

Source

reader.lisp (file)

Special Variable: *plists-are-lists*

If T, PLISTS will not be treated specially by READER:GET-VAL method for lists.

Package

reader

Source

reader.lisp (file)

Special Variable: *set-function*

A symbol bound (at read-time) to a function that takes (LIST &KEY TEST)
as arguments and returns the set.

Package

reader

Source

reader.lisp (file)

5.1.2 Macros

Macro: disable-reader-syntax ()

Package

reader

Source

reader.lisp (file)

Macro: enable-reader-syntax &rest READER-MACRO-IDENTIFIERS

READER-MACRO-IDENTIFIERS are any of the following symbols: GET-VAL, HASH-TABLE, NOT, STRING, DESCRIBE, ARRAY, SET, RUN-PROGRAM

Package

reader

Source

reader.lisp (file)

5.1.3 Generic functions

Generic Function: get-val OBJECT &rest KEY/S

Package

reader

Source

reader.lisp (file)

Writer

(setf get-val) (generic function)

Methods

Method: get-val (OBJECT array) &rest KEY/S

Method: get-val (OBJECT list) &rest KEY/S

Method: get-val (OBJECT hash-table) &rest KEY/S

Method: get-val (OBJECT sequence) &rest KEY/S

Method: get-val (OBJECT structure-object) &rest KEY/S

Generic Function: (setf get-val) G0 OBJECT &rest KEY/S

Package

reader

Reader

get-val (generic function)

Methods

Method: (setf get-val) NEW-VALUE (OBJECT array) &rest KEY/S

Source

reader.lisp (file)

Method: (setf get-val) NEW-VALUE (OBJECT list) &rest KEY/S

Source

reader.lisp (file)

Method: (setf get-val) G0 (OBJECT hash-table) &rest KEY/S

Source

reader.lisp (file)

Method: (setf get-val) G0 (OBJECT sequence) &rest KEY/S

Source

reader.lisp (file)

Method: (setf get-val) G0 (OBJECT structure-object) &rest KEY/S

Source

reader.lisp (file)

Method: (setf get-val) G0 (OBJECT standard-object) &rest KEY/S

Source

reader.lisp (file)

5.2 Internal definitions

5.2.1 Constants

Constant: +reader-macro-doc+

Package

reader

Source

reader.lisp (file)

5.2.2 Special variables

Special Variable: *previous-readtables*

Package

reader

Source

reader.lisp (file)

Special Variable: *reader-macro-activation-functions*

Package

reader

Source

reader.lisp (file)

5.2.3 Macros

Macro: defmethods-with-setf FUN-NAME LAMBDA-LIST &rest METHODS

Package

reader

Source

reader.lisp (file)

Macro: setp NEW-VALUE PLACE

Package

reader

Source

reader.lisp (file)

Macro: with-env &body BODY

Package

reader

Source

reader.lisp (file)

Macro: with-reader-syntax READER-MACRO-IDENTIFIERS &body BODY

This macro is only made for use by read-and-eval functionality, and rather directed towards tests than users. So, do not export.

Package

reader

Source

reader.lisp (file)

5.2.4 Functions

Function: %enable-reader-syntax READTABLE &rest READER-MACRO-IDENTIFIERS

Package

reader

Source

reader.lisp (file)

Function: array-reader-macro STREAM CHAR N

Package

reader

Source

reader.lisp (file)

Function: describe-reader-macro STREAM CHAR

Package

reader

Source

reader.lisp (file)

Function: er STRING

Package

reader

Source

reader.lisp (file)

Function: get-val-reader-macro STREAM CHAR

Package

reader

Source

reader.lisp (file)

Function: hash-table-reader-macro STREAM CHAR

Package

reader

Source

reader.lisp (file)

Function: list-to-hash-set-with-test LIST &key TEST

Package

reader

Source

reader.lisp (file)

Function: make-t-array-from-initial-contents INITIAL-CONTENTS

Package

reader

Source

reader.lisp (file)

Function: not-reader-macro STREAM CHAR

Package

reader

Source

reader.lisp (file)

Function: read-array STREAM

Package

reader

Source

reader.lisp (file)

Function: read-row-from-string STRING

Package

reader

Source

reader.lisp (file)

Function: read-stream-as-string-until STREAM UNTIL-CHAR

Package

reader

Source

reader.lisp (file)

Function: read-stream-until STREAM UNTIL-CHAR

Package

reader

Source

reader.lisp (file)

Function: run-program-reader-macro STREAM CHAR N

Package

reader

Source

reader.lisp (file)

Function: set-reader-macro STREAM CHAR N

Package

reader

Source

reader.lisp (file)

Function: string-reader-macro STREAM CHAR

Package

reader

Source

reader.lisp (file)

Appendix A Indexes

A.1 Concepts

A.2 Functions

A.3 Variables

A.4 Data types