Module talk:Strip to numbers

Current problems

Fixed

Obvious known issues:

• Matches all numbers, hyphen-minuses, and dots, and will:
  • produce an invalid number from input like font-size: -10% (resolves to --10) or approx. 53.5 (resolves to .53.5)
  • the opposite of the desired number for cases like margin-left: 2.5em (resolves to -2.5)
  • probably-undesired concatenation from input like 42 chickens on 12 farms (resolves to 4212)

It needs to only match on - and . when preceding a numeral, and to stop parsing and return a value when it reaches the first end of numeric data.  — SMcCandlish ☺ ☏ ¢ ≽^ʌⱷ҅_ᴥⱷ^ʌ≼  10:35, 18 July 2015 (UTC)

WOSlinker's rewrite fixed all this.  — SMcCandlish ☺ ☏ ¢ ≽^ʌⱷ҅_ᴥⱷ^ʌ≼  16:53, 18 July 2015 (UTC)

For later development

A more advanced version that could be invoked directly or required by other modules, might do something like this:

• For any arbitrary input, trim all leading material until it hits any of:
  • a numeral; or
  • a . followed by a numeral; or
  • a - or the proper negative/minus glyph − followed by either of:
    • a numeral, or by
    • . followed by a numeral
• then retain that character;
• proceed to next character, and retain it if matches either:
• a numeral, or
• a ., unless one was matched earlier;
• repeat until that fails (i.e. a second . is found, or any other non-numeral is found);
• then trim everything after that;
• and do all this for multiple values passed,
• and even do it for multiple numbers found in the same value (or discard any found after the first, or something)
• In the division function:
  • Accept arbitrary divisors;
  • Round the results to arbitrary decimal places if necessary (default: two, as in 23.48).

A later super-badass version could add:

• recognize ^ or e, and x or × or * when found in a context that indicates an exponent (23.5x10^8), and a few other such cases (e.g. characters used to indicate a truncated long/endless decimal)
• find multiple numbers per input string, and separate them by something (e.g. a space or a comma) depending on which function is invoked
• recognize simple formulae
• recognize English words for numbers and convert to use digits

 — SMcCandlish ☺ ☏ ¢ ≽^ʌⱷ҅_ᴥⱷ^ʌ≼  10:35, 18 July 2015 (UTC)