tibetan-precomposition-rule-regexp

tibetan-precomposition-rule-regexp is a variable defined in `tibetan.el'.
Its value is

"\\(ཕྱྭ\\|གྲྭ\\|ཚྭ\\|རྩྭ\\|རྒྭ\\|རྐྱ\\|རྒྱ\\|རྨྱ\\|སྐྱ\\|སྒྱ\\|སྤྱ\\|སྦྱ\\|སྨྱ\\|སྐྲ\\|སྒྲ\\|སྣྲ\\|སྤྲ\\|སྦྲ\\|སྨྲ\\|ཁྭ\\|ཉྭ\\|ཙྭ\\|ཞྭ\\|ཤྭ\\|ཁྱ\\|ཕྱ\\|ཁྲ\\|ཐྲ\\|ཕྲ\\|ཤྲ\\|ཛྲ\\|རྔ\\|རྙ\\|རྩ\\|རྫ\\|ལྔ\\|སྔ\\|སྙ\\|སྩ\\|ཀྭ\\|གྭ\\|ཅྭ\\|ཏྭ\\|དྭ\\|ཟྭ\\|རྭ\\|ལྭ\\|སྭ\\|ཧྭ\\|ཀྱ\\|གྱ\\|པྱ\\|བྱ\\|མྱ\\|ཀྲ\\|གྲ\\|ཏྲ\\|དྲ\\|པྲ\\|བྲ\\|མྲ\\|སྲ\\|ཧྲ\\|ཇྲ\\|ཀླ\\|གླ\\|བླ\\|ཟླ\\|རླ\\|སླ\\|རྐ\\|རྒ\\|རྗ\\|རྟ\\|རྡ\\|རྣ\\|རྦ\\|རྨ\\|ལྐ\\|ལྒ\\|ལྣ\\|ལྕ\\|ལྗ\\|ལྟ\\|ལྡ\\|ལྤ\\|ལྦ\\|ལྷ\\|སྐ\\|སྒ\\|སྟ\\|སྡ\\|སྣ\\|སྤ\\|སྦ\\|སྨ\\)"

Documentation:
Regexp string to match a sequence of Tibetan consonantic components, i.e.,
one base consonant and one or more subjoined consonants.
The result of matching is to be used for indexing alist when the component
sequence is converted to the corresponding precomposed glyph.
This also matches some punctuation characters which need conversion.