Tokens::fromCode - add caching to speedup - for #398 issue.
bug #402 Tokens::fromCode - add caching to speedup - for #398 issue. (keradus)

This PR was squashed before being merged into the 0.5.x-dev branch (closes #402).

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Tokens::fromCode - add caching to speedup - for #398 issue.

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b80fc74 Tokens::fromCode - add caching to speedup - for #398 issue.