moremacros

(always BODY...) -> proceduresyntax: Returns a procedure/0 that always evaluates & returns the result of BODY.... Caching is not performed, unlike constantly.

switch

(switch EXP ((KEY ...) EXP1 ...) ... [(else EXPn ...)])syntax: This is similar to case, but the keys are evaluated & equal? is the test.

type-case

(type-case EXPRESSION [(TYPE-CASE BODY ...) ...]))syntax

Expands into a form that selects a TYPE-CASE based on the type of the EXPRESSION.

A TYPE-CASE is:

symbol: the base name of a type predicate
(symbol symbol...): a list of base names
else: an else clause

The actual name of the predicate is built from the base name and a ? suffix. So a base name number has the predicate number?.

(import moremacros)

(type-case 23
  ((symbol string char) 'symbolic)
  (number               'numeric)
  (else                 'otheric) )
;=> numeric

type-case*

(type-case* EXPRESSION [(TYPE-TEST BODY ...) ...]))syntax

Like type-case but binds local variable it to the value of EXPRESSION.

(import moremacros)

(type-case* 23
  ((symbol string char) (list it 'symbolic) )
  (number               (list it 'numeric) )
  (else                 (list it 'otheric) ) )
;=> (23 numeric)

whennot

(whennot TEST [BODY ...]))syntax: Synonym for unless.

swap!

(swap! VAR1 VAR2))syntax

Swap settings of VAR1 & VAR2.

Variable specific version of miscmacros (exchange! VAR1 VAR2) so lower overhead.

set!-op

(set!-op VAR OP ARG...))syntax

Sets VAR to the value of (OP ARG...), where an occurrence of <> in ARG... is replaced with VAR.

When there is no occurrence of <> in ARG... the template (OP <> ARG...) is used.

Similar to the C language family <l-value> <bin-op-assign> <r-value>.

assure

(assure EXPRESSION [ERROR-ARGUMENT...]))syntax: When EXPRESSION yields value #f invoke (error ERROR-ARGUMENT...), otherwise return value.

define-reference-let

(define-reference-let NAME REFERENCE-FUNCTION)syntax

NAME is a symbol, the name of the generated reference-let macro.

REFERENCE-FUNCTION is a (procedure (* * *) *) with arguments:

The REFERENCE-FUNCTION is to return the value for KEY in the TABLE, otherwise the DEFAULT value.

The generated macro has the signature:

(NAME TABLE (VAR | (VAR) | (VAR KEY [DEFAULT]) ...) BODY ...)syntax

TABLE: some data-structure instance that reifies a set of key+value abstraction
KEY: identifier for a possible entry in the TABLE
DEFAULT: in case an entry for the KEY does not exist

Decompose TABLE entries into variable bindings. Should the KEY not be a symbol, or the desired variable name VAR, as 'VAR, is not the key, the (VAR KEY [DEFAULT]) form can be used.

The default for DEFAULT is #f.

The BODY... is evaluated with the specified bindings.

See hash-let for an example of import.

warning-guard

(warning-guard GETTER-NAME TYPENAME [BODY...])syntax

Constructs a variable or parameter guard procedure that generates a warning and returns the current value when the type predicate fails, otherwise the submitted value is returned.

TYPENAME is an identifier and TYPENAME? is a (procedure (*) boolean).

GETTER-NAME is an identifier and the name of a procedure _ *.

BODY is zero or more expressions that are performed after a successful typecheck with obj bound to the new parameter value. Note that since the guard is invoked by a variable or parameter during initialization, so will be the body code.

(warning-guard some-var integer)

checked-guard

(checked-guard GETTER-NAME TYPENAME [BODY...])syntax

Constructs a variable or parameter guard procedure that uses a type check procedure to verify the submitted value is returned.

TYPENAME is an identifier and check-TYPENAME is a (procedure ((or #f symbol) * #!optional (or symbol string)) *). See check-errors for a suite of these procedures.

GETTER-NAME is an identifier and the name of a procedure _ *.

(import (type-checks-numbers integer))

(checked-guard some-var natural-integer)

define-warning-parameter

(define-warning-parameter NAME INIT TYPENAME [BODY...])syntax

Wrapper around define-parameter and warning-guard that defines the parameter NAME to the parameter.

NAME is an identifier.

INIT is some Scheme object.

TYPENAME is an identifier. The basename of a type predicate; see warning-guard.

BODY... as for warning-guard.

(define-warning-parameter scale * procedure)
(scale 23) ;=> Warning: (scale) "bad argument type - not a procedure" 23

define-checked-parameter

(define-checked-parameter NAME INIT TYPENAME [BODY...])syntax

Wrapper around define-parameter and checked-guard that defines the variable NAME to the parameter.

NAME is an identifier.

INIT is some Scheme object.

TYPENAME is an identifier. The basename of a type predicate; see checked-guard.

BODY... as for checked-guard.

(define-checked-parameter scale * procedure)
(scale 23) ;=> Error: (scale) bad argument type - not a procedure: 23

hash-let

Usage

(import hash-let)

hash-let

(hash-let HASH-TABLE (VAR | (VAR) | (VAR KEY [DEFAULT]) ...) BODY ...)syntax

Decompose HASH-TABLE entries into variable bindings. Should the KEY not be a symbol, or the desired variable name VAR is not the key, the (VAR KEY [DEFAULT]) form can be used.

The default value for a missing hash-table entry is #f but can be specified with the (VAR KEY DEFAULT) form.

The BODY... is evaluated with the specified bindings.

(import hash-let (srfi 69))

(let ((tbl (make-hash-table)))
  ;set!
  (hash-table-set! tbl 'abc "commercial network")
  (hash-table-set! tbl "nbc" "commercial network")
  ;ref
  (hash-let tbl
    ((abc)                              ;key symbol 'abc
     (cbs "nbc")                        ;supplied string key
     (pbs (string-append "p" "bs") #t)  ;default value for missing "pbs"
     tbs)                               ;missing key symbol 'tbs
    (print 'abc " is a " abc)
    (print "cbs" " is a " cbs)
    (print (string-append "p" "bs") " is a " pbs)
    (print 'tbs " is a " tbs) ) )
;=>
abc is a commercial network
cbs is a commercial network
pbs is a #t
tbs is a #f

Numeric Macros

Usage

(import numeric-macros)

one?

two?

three?

four?

five?

six?

seven?

eight?

nine?

ten?

(one? OBJ)syntax
(two? OBJ)syntax
(three? OBJ)syntax
(four? OBJ)syntax
(five? OBJ)syntax
(six? OBJ)syntax
(seven? OBJ)syntax
(eight? OBJ)syntax
(nine? OBJ)syntax
(ten? OBJ)syntax: Numeric value predicates.

1+

1-

(1+ VAL) -> numbersyntax
(1- VAL) -> numbersyntax: Alias add1 & sub1.

++

--

(++ VAL) -> numbersyntax
(-- VAL) -> numbersyntax: Alias 1+ & 1-.

fx++

fx--

(fx++ VAL) -> fixnumsyntax
(fx-- VAL) -> fixnumsyntax: Fixnum increment & decrement.

fp++

fp--

(fp++ VAL) -> flonumsyntax
(fp-- VAL) -> flonumsyntax: Flonum increment & decrement.

fl++

fl--

(fl++ VAL) -> flonumsyntax
(fl-- VAL) -> flonumsyntax: R6/7RS synonyms.

!+!

1-!

(1+! VAR) -> numbersyntax

(1-! VAR) -> numbersyntax

Mutating increment & decrement. Returns mutated value.

VAR must be a variable.

++!

--!

(++! VAR) -> numbersyntax
(--! VAR) -> numbersyntax: Alias 1+! & 1-!.

fx++!

fx--!

(fx++! VAR) -> fixnumsyntax

(fx--! VAR) -> fixnumsyntax

Mutating fixnum increment & decrement. Returns mutated value.

VAR must be a variable.

fp++!

fp--!

(fp++! VAR) -> flonumsyntax

(fp--! VAR) -> flonumsyntax

Mutating flonum increment & decrement. Returns mutated value.

VAR must be a variable.

fl++!

fl--!

(fl++! VAR) -> flonumsyntax
(fl--! VAR) -> flonumsyntax: R6/7RS fp! synonyms.

variable-item

Usage

(import variable-item)

make-variable

make-variable INIT #!optional GUARDprocedure

Returns a procedure whose behavior is that of a parameter, except for the fact that it is not a parameter. The closed-over value is not thread-local.

INIT is some Scheme object that meets the constraint enforced by the GUARD.

GUARD is a (procedure (*) *) returning an acceptable value for the variable. Default is identity.

Supports SRFI 17.

define-variable

(define-variable NAME INIT [GUARD])syntax

Wrapper around make-variable that defines the variable NAME to the variable.

NAME is an identifier.

INIT and GUARD as for make-variable.

(import variable-item)

(define-variable scale * (warning-guard scale procedure))
(scale) ;=> #<procedure ...>
(scale /)

define-warning-variable

(define-warning-variable NAME INIT TYPENAME [BODY...])syntax

Wrapper around make-variable and warning-guard that defines the variable NAME to the variable.

NAME is an identifier.

INIT is some Scheme object.

TYPENAME is an identifier. The basename of a type predicate; see warning-guard.

BODY... as for warning-guard.

(import variable-item)

(define-warning-variable scale * procedure)
(scale 23) ;=> Warning: (foo) "bad argument type - not a procedure" 23

define-checked-variable

(define-checked-variable NAME INIT TYPENAME [BODY...])syntax

Wrapper around make-variable and checked-guard that defines the variable NAME to the variable.

NAME is an identifier.

INIT is some Scheme object.

TYPENAME is an identifier. The basename of a type predicate; see checked-guard.

BODY... as for checked-guard.

(use variable-item)

(define-checked-variable scale * procedure)
(scale 23) ;=> Error: (foo) "bad argument type - not a procedure" 23

Requirements

srfi-69 miscmacros check-errors

test test-utils

Author

Kon Lovett

Repository

This egg is hosted on the CHICKEN Subversion repository:

https://anonymous@code.call-cc.org/svn/chicken-eggs/release/5/moremacros

If you want to check out the source code repository of this egg and you are not familiar with Subversion, see this page.

Version history

2.5.3: ++ & -- return mutated.
2.5.2: Fix ++ & --.
2.5.1: Fix warning-guard & error-guard variable injection of obj.
2.5.0: Add always. Fix warning-guard error path.
2.4.0: Add variable-item (back).
2.3.0: .
2.2.8: .
2.2.7: .
2.2.6: Add true, false, true?, and false?.
2.2.5: .
2.2.4: Fix warning-guard.
2.2.3: __date__ uses %F.
2.2.2: Add 1+ & 1- to numeric-macros. Move __line__ & friends to cpp-macros.
2.2.1: Update macros.
2.2.0: Added __line__ & friends. (inspired by Kooda on #chicken irc)
2.1.0: Added switch, one? & friends.
2.0.0: CHICKEN 5 release.

License

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the Software), to deal in the Software without restriction, including without limitation the rights to import, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED ASIS, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

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