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Directed graph in adjacency list format.
The digraph library is an implementation of a directed graph, where the edges are stored as adjacency lists indexed by node number.
The library defines a digraph "object" -- a procedure that takes a method name as a symbol, and returns the procedure that implements the respective operation.
Directed graph procedures
The digraph object is created by procedure make-digraph, which is the only user-visible procedure defined in this egg:[procedure] make-digraph:: NAME INFO [NODE-LIST [SUCC-LIST [PRED-LIST]]] -> SELECTOR
where NAME is the graph name (string or symbol), INFO is an optional metadata object of an arbitrary type or #f; NODE-LIST is an optional list of nodes to be inserted in the graph; each element of the list must be of the form (N INFO) where N is a unique node number (integer), and INFO is an optional metadata object describing the node. Similarly, SUCC-LIST and PRED-LIST can be used to define the graph edges upon graph creation. If supplied, these arguments must be lists in which every element is of the form (I J INFO), where I and J are node numbers, and INFO is an optional metadata object.
The returned selector procedure can take one of the following arguments:
|'name||returns the graph name (string or symbol)|
|'info||returns the graph metadata (arbitrary type)|
|'new-id!||returns a procedure with no arguments, which returns the lowest available node number|
|'add-node!||returns a procedure LAMBDA N INFO which inserts in the graph node with number N and metadata INFO; if the node already exists in the graph, it will be overwritten with the new metadata|
|'add-edge!||returns a procedure LAMBDA EDGE which inserts in the graph the specifed edge; the edge is given by a list of the form (I J INFO), where I and J are source and destination nodes, respectively, and INFO is edge metadata of arbitrary type|
|'remove-node!||returns a procedure LAMBDA N which removes node N and all its edges from the graph|
|'nodes||returns a procedure with no arguments, which returns a list with the nodes of the graph and their metadata|
|'edges||returns a procedure with no arguments, which returns a list with the edges of the graph and their metadata|
|'roots||returns a procedure with no arguments, which returns a list with all nodes in the graph that do not have an predecessor|
|'order||returns a procedure with no arguments, which returns the number of nodes in the graph|
|'size||returns a procedure with no arguments, which returns the number of edges in the graph|
|'capacity||returns a procedure with no arguments, which returns the size of the underlying dynamic vector|
|'succ||returns a procedure LAMBDA N which returns a list with the successor nodes of node N|
|'pred||returns a procedure LAMBDA N which returns a list with the predecessor nodes of node N|
|'succ-list||returns a procedure with no arguments which returns a list containing the successor nodes for each node.|
|'pred-list||returns a procedure with no arguments which returns a list containing the predecessor nodes for each node.|
|'out-edges||returns a procedure LAMBDA N which returns a list with the outgoing edges of node N|
|'in-edges||returns a procedure LAMBDA N which returns a list with the incoming edges of node N|
|'has-edge||returns a procedure LAMBDA I J which returns true if edge I -> J exists in the graph and false otherwise|
|'has-node||returns a procedure LAMBDA N which returns true if node N exists in the graph and false otherwise|
|'node-info||returns a procedure LAMBDA N which returns the metadata for node N|
|'node-info-set!||returns a procedure LAMBDA N V which sets the metadata for node N|
|'foreach-node||returns an iterator procedure LAMBDA F which iterates over the nodes in the graph by invoking function F on the node number and metadata of each node|
|'foreach-edge||returns an iterator procedure LAMBDA F which iterates over the edges in the graph by invoking function F on each edge|
|'debug||returns a list with the internal representation of the graph|
;; example adapted from graph example in the Boost library documentation (require-extension srfi-1) (require-extension digraph) (define g (make-digraph 'depgraph "dependency graph")) (define used-by (list (cons 'dax_h 'foo_cpp) (cons 'dax_h 'bar_cpp) (cons 'dax_h 'yow_h) (cons 'yow_h 'bar_cpp) (cons 'yow_h 'zag_cpp) (cons 'boz_h 'bar_cpp) (cons 'boz_h 'zig_cpp) (cons 'boz_h 'zag_cpp) (cons 'zow_h 'foo_cpp) (cons 'foo_cpp 'foo_o) (cons 'foo_o 'libfoobar_a) (cons 'bar_cpp 'bar_o) (cons 'bar_o 'libfoobar_a) (cons 'libfoobar_a 'libzigzag_a) (cons 'zig_cpp 'zig_o) (cons 'zig_o 'libzigzag_a) (cons 'zag_cpp 'zag_o) (cons 'zag_o 'libzigzag_a) (cons 'libzigzag_a 'killerapp))) (define node-list (delete-duplicates (concatenate (list (map car used-by) (map cdr used-by))))) (define node-ids (list-tabulate (length node-list) values)) (for-each (lambda (i n) ((g 'add-node!) i n)) node-ids node-list) (define node-map (zip node-list node-ids)) (for-each (lambda (e) (match e ((ni . nj) (let ((i (car (alist-ref ni node-map))) (j (car (alist-ref nj node-map)))) ((g 'add-edge!) (list i j (format "~A->~A" ni nj))))) (else (error "invalid edge " e)))) used-by) (print ((g 'nodes))) (print ((g 'edges))) ((g 'remove-node!) 0) (print ((g 'nodes))) (print ((g 'edges)))
About this egg
- Converted documentation to wiki format
- Ported to Chicken 4
- Now using matchable extension
- Added procedures pred-list and succ-list
- Added procedure node-info-set!
- Build script updated for better cross-platform compatibility
- Test infrastructure changed to use testbase
- Bug fixes in set-out-edges! and set-in-edges! [thanks to Andreas Scholta]
- License upgrade to GPL v3
- Updated the roots procedure to match the documentation
- Minor changes to the setup script
- Added support for chicken-setup -test
- Initial release
Copyright 2007-2010 Ivan Raikov and the Okinawa Institute of Science and Technology This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. A full copy of the GPL license can be found at <http://www.gnu.org/licenses/>.