the scanner/symbols.go is lifts directly the array of symbol definitions
https://raw.githubusercontent.com/asciimath/asciimathml/master/ASCIIMathML.js
with edits to make it compile in Go.
The scanner is defined in scanner/scanner.go. It is extremely simple as it
builds a regexp out of the symbols array and uses is Regexp.FindAllStringIndex
to extract the tokens.
It seems to work as the tests in scanner/scanner_test.go show. Would be
better to return token data rather than just token strings though!