85 lines
2.7 KiB
Scheme
85 lines
2.7 KiB
Scheme
(define (declare-node node-text node-generation)
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(string-append (number->string node-generation)
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"[label=\""
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node-text
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"\"];"))
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(define (make-link previous-node current-node)
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(string-append (number->string previous-node) " -- "
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(number->string current-node) ";"))
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(define (tree-to-dot-helper tree current-generation previous-generation)
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;; Helper to ~tree-to-dot~ that translates a Scheme tree with any number of
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;; children per node to a corresponding graphviz file that can be executed from
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;; dot.
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;; Arguments:
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;; - tree :: tree to convert
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;; - current-generation :: Generation number, incremented when changing from a node
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;; to another node from the same generation, multiplied by 10 when going from
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;; a node to one of its children.
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;; - previous-generation :: Generation number from previous named node
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(cond ((null? tree) "")
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((atom? (car tree)) ;; '("text" () () ())
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(string-append (declare-node (car tree) current-generation)
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(make-link previous-generation current-generation)
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(tree-to-dot-helper (cdr tree)
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(+ 1 (* 10 current-generation))
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current-generation)))
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((list? (car tree)) ;; '(() () () ())
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(string-append (tree-to-dot-helper (car tree) ;; child of current node
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current-generation
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previous-generation)
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(tree-to-dot-helper (cdr tree) ;; sibling of current node
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(+ 1 current-generation)
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previous-generation)))))
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(define (tree-to-dot tree)
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;; Returns a graphviz’s dot-compatible string representing a Scheme tree
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(if (null? tree) ""
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(string-append
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"graph{node[shape=plaintext];graph[bgcolor=\"transparent\"];"
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(declare-node (car tree) 0)
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(tree-to-dot-helper (cdr tree) 1 0)
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"}")))
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(define vowels
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'("[vowel]"
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("[back]"
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("[tense]"
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("[high]" ("ü"))
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("{high}" ("ö")))
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("{tense}"
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("[high]" ("u"))
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("{high}" ("o"))))
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("{back}"
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("[tense]"
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("[high]" ("y"))
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("{high}" ("ë")))
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("{tense}"
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("[high]" ("i"))
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("{high}" ("e"))))))
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(define syntax-tree
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'("S"
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("Obl")
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("S'"
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("NPerg"
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("NP"))
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("VP"
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("NPdat"
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("NP"))
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("VP'"
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("NPabs"
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("NP"
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("S")
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("NP'"
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("Adj")
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("N"))))
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("V'"
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("Mood")
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("Tense")
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("V")
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("Neg")))))))
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(display (tree-to-dot vowels))
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