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Diffstat (limited to 'txr.1')
| -rw-r--r-- | txr.1 | 58 |
1 files changed, 58 insertions, 0 deletions
@@ -14938,6 +14938,64 @@ while at the same time still modifying the internals of <trie>. Consequently, the program should not retain the input object <trie>, but use the returned object in its place. +.SS Function trie-lookup-begin + +.TP +Syntax: + + (trie-lookup-begin <trie>) + +.TP +Description: + +The trie-lookup-begin function returns a context object for performing +an open-coded lookup traversal of a trie. The <trie> argument +is expected to be a trie that was created by the make-trie function. + +.SS Function trie-lookup-feed-char + +.TP +Syntax: + + (trie-lookup-feed-char <trie-context> <char>) + +.TP +Description: + +The trie-lookup-feed-char function performs a one character step in a trie +lookup. The <trie-context> argument must be a trie contxt returned +by trie-lookup-begin, or by some previous call to trie-lookup-feed-char. +The <char> argument is the character to search for. + +If the lookup is successful (the match through the trie can continue +with the given character) then a new trie context object is returned. +The old trie context remains valid. + +If the lookup is unsuccessful, nil is returned. + +Note: determining whether a given string is stored in a trie can be +performed looking up every character of the string successively +with trie-lookup-feed-char, using the newly returned context +for each successive operation. If every character is found, it means +that either that exact string is found in the trie, or a prefix. +The ambiguity can be resolved by testing whether the trie has a value +at the last node using tree-value-at. For instance, if "catalog" +is inserted into an empty trie with value "foo", then "cat" will look up +successfully, being a prefix of "catalog"; however, the value at "cat" is nil. + +.SS Function tree-value-at + +.TP +Syntax: + + (trie-value-at <trie-context>) + +.TP +Description: + +The trie-value-at function returns the value stored at the node in +in the trie given by <trie-context>. Nodes which have not been given +a value hold the value nil. .SS Function filter-string-tree |