Trie library for use with cspell
This library allows easily building of a Trie from a word list.
The resulting trie can then be compressed into a DAFSA|DAWG.
cspell-trie is both a tool and a library.
Give a list of words, cspell-trie will turn it into a trie file.
npm install -g cspell-trie
cspell-trie --help
cspell-trie create filename.txt -o filename.trie
cspell-trie reader filename.trie
TrieXv1
base=10
The header has two parts.
- TrieXv1 -- the identifiers
- base -- offsets are stored using the base (10, 16, 32) are common. higher the base, the smaller the file. Max is 36
The first line of data is always a *
Each line is a node in the Trie.
The format of each line is:
star [char index [, char index]*]
- star - the presence of a star indicates that the node is the ending of a word.
- char - a character that can be appended to the word followed by the node at index.
- index - the offset in the list of nodes to continue appending
In other words, each line has an optional *
followed by 0 or more (char, index) pairs.
A missing index implies an index of 0, which is the end of word flag.
Example Line: *s1,e
-- The word can stop here, or add an s and continue at node 1, or add an e
Word List:
- walk
- walked
- walker
- walking
- walks
- talk
- talks
- talked
- talker
- talking
becomes
Output: (Offsets are added for clarity, but do not exist in output)
Offset Output
------- --------
TrieXv1
base=10
0 *
1 d,r
2 g
3 n2
4 *e1,i3,s
5 k4
6 l5
7 a6
8 t7,w7
The root of the trie is the last offset, 8. It is designed for the entire trie to be in memory, which is why the root is at the end. This allows for efficiently building the trie as the file loads line by line, because each line can only refer to previous lines.
How to walk the data to see if "talks" is in it.
- Start with the root at offset 8.
- t found goto 7
- a found goto 6
- l found goto 5
- k found goto 4
- s found stop (goto 0 is stop).