procedure-surface
![[Picture of an egg]](egg.jpg)
Generic Programming Support
Warning - procedure surface is experimental!
The procedure-surface egg provides a facility for generic programming in Scheme, similar in purpose to the "structures" egg. Unlike the normal pattern of use for "structures" this facility will delay loading of any library or extension until an actual binding is required. The use of a 'define' form as a procedure reference with 'make-procedure-means' is not supported, unlike the analogous 'structure' from "structures".
Odd names are used for parsimony. Read 'interface' for 'surface', and 'implementation' for 'means'.
Sets the symbol NAME to the described procedure surface. Uses NAME as the keyword argument #:name for the surface. See 'make-procedure-surface' for argument descriptions.
Sets the symbol NAME to the described procedure surface means. See 'make-procedure-means' for argument descriptions.
Invoke the procedure identified by PROC-SYM in the MEANS with the ARG ... list.
Apply the procedure identified by PROC-SYM in the MEANS to the ARG ... list.
Bind the local symbol(s) PROC-SYM ... to the corresponding procedure(s) in the MEANS and evaluate the BODY.
Abbreviation of 'call-thru-procedure-means'.
Abbreviation of 'apply-thru-procedure-means'.
Abbreviation of 'let-procedure-means'.
Returns a procedure signature for IDENTIFIER with CONTRACT.
The contract grammar is described below. Can be null, '(), for no contract.
Is OBJECT a procedure signature?
Returns the procedure signature identifier of the SIGNATURE.
Returns the procedure signature contract of the SIGNATURE.
Creates and returns a procedure surface. A collection of procedure identifiers and contracts.
| immutable: | A boolean. Immutable (#t) or mutable (#f). |
| name: | A symbol or string. The name of the surface. When missing a name of the form "ps#" will be created. |
| PROC-SYM | A symbol. The procedure identifier. |
| CONTRACT | A list. The source form of a procedure signature. The contract grammar is described below. null, '(), for no contract. |
Is the OBJECT a procedure surface?
Returns the name, or names as list if composite, of the SURFACE.
Is the SURFACE immutable?
Is the SURFACE mutable?
Returns the procedure signature of the SURFACE.
Adds or updates procedure signatures in SURFACE.
Removes the procedure signature for PROC-SYM from SURFACE.
Returns a alist, (<procedure-symbol> . <procedure-signature>), from SURFACE.
Returns a procedure surface, the combination of SURFACE ... set. Should any surface be immutable then the composite is immutable.
Is the SURFACE a composite?
Supply procedures for the SURFACE.
| immutable: | A boolean. Immutable (#t) or mutable (#f). |
| extension: | A symbol or string. The name of the extension. |
| library: | A symbol or string. The name of the library. |
| pathname: | A string. The absolute pathname of the extension or library. Required when the extension or library is not in the Chicken repository. |
| PROC-SYM | A symbol. The procedure identifier. Must match a procedure identifier from SURFACE. |
| PROC-REF | A boolean, symbol, or procedure. The procedure alias when a symbol. When boolean use the procedure identifier as the alias. Otherwise this should be a procedure. |
Is the OBJECT a procedure surface?
Are the MEANS immutable?
Are the MEANS mutable?
Returns the alias of PROC-SYM in MEANS.
Returns the current binding of PROC-SYM in the MEANS, which maybe the unbound value.
Forces a load, if necessary. Returns the current binding of PROC-SYM in the MEANS, which maybe the unbound value.
Returns the procedure surface, or a list of procedure surface when composite, that the MEANS implements.
Are all procedures in the procedure surface(s) of the MEANS declared?
Are all the procedures in the MEANS bound?
Returns an alist, (<procedure identifier> . <procedure surface>), of all procedures in the procedure surface(s) of the MEANS ... that are undeclared.
Returns an alist, (<procedure-symbol> . <procedure-surface>), of all the unbound procedures in MEANS.
Is the procedure identified by PROC-SYM without a declaration in the MEANS?
Returns an alist, (<procedure-symbol> . <procedure-alias/closure), from the MEANS.
Adds or updates procedures for an existing MEANS.
Removes the procedure PROC-SYM from the MEANS.
Load of any libraries and extensions required by the MEANS.
Returns a procedure means, the combination of MEANS ... set. Should any means be immutable then the composite is immutable.
Are the MEANS a composite?
Is this surface means procedure loaded?
Returns the top level binding, if any, for the procedure named SYMBOL.
The signature type system supports multiple-inheritance, via the 'extends' property.
Creates all the builtin types.
Creates a new signature type object.
| NAME | A symbol. The name of the new type. |
| EXTENDS | A symbol or list. The type(s) that the new type is extending. |
| PREDICATE | A procedure. Determines whether an arbitrary object is a value of the new type. |
| SPECIALIZER | A procedure. Determines whether a specialization for the new type is valid. |
Is OBJECT a signature type?
Does a type extend TYPE/NAME.
Does TYPE/NAME not extend a type?
Does TYPE/NAME-SUB extend TYPE/NAME-SUPER?
The most distant ancestor of all Scheme types is 'object'. However, roots are not considered when determining the kind of relationship from an intermediate type. So to check if a type is a kind of 'object' do so directly.
Returns the signature type for NAME.
Returns the name of TYPE.
Returns the predicate for TYPE/NAME.
Returns the specializer for TYPE/NAME.
Return a list of the types that TYPE/NAME extends.
Return a list of the types that extend TYPE/NAME.
Remove the TYPE/NAME.
Replace the existing TYPE/NAME with a new definition.
Validates the source form of a contract and returns the internal form.
| contract | <map> | (or <map> ...) |
| type | <symbol> | <specialization> |
| specialization | <map> | (<type> [<parameter> ...]) | (or <type> ...) |
| parameter | <object> |
| domain | [<type> ...] [#!optional <type> ...] [#!rest list | (list <type> ...)] [#!key (<keyword> <type>) ...] |
| range | <type> | (values <type> ...) |
| map | (-> <domain> <range> [<throw> ...]) |
| throw | (signals <exception> ...) | (aborts <exception> ...) |
| exception | <symbol> | (<symbol> ...) |
A <map> is a specialization of '->', the type of a procedure.
'()' is a synonym of 'null' for this grammar.
Example: (-> (array (rank 2)) object (values integer complex vector object)) - a procedure (<map>) taking a matrix & any object, returning 4 multiple values.
Copyright (c) 2006, Kon Lovett. All rights reserved. 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 use, 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.