Lexicon search with regex does not handle separator correctly

[bikibird]

Describe the bug
For ishml.Lexicon.search() using regex does not handle separator correctly resulting in a failed search .

var lexicon=ishml.Lexicon()
lexicon.search("123",{regex:/^-?([0-9]*[.])?[0-9]+/})

returns empty array in error.

lexicon.search("123 ",{regex:/^-?([0-9]*[.])?[0-9]+/})

correctly returns an array containing token for 123 with a "fuzzy" definition.