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Fontastic Programming — Addition Font

posted by chromas on Thursday March 14 2019, @04:44AM   
from the the-whole-is-greater-than-the-sum-of-the-parts dept.

martyb writes:

What if someone discovered that the specifications in a font file could be Turing complete? What if that person realized that a font could, therefore, perform computations. How about addition?

Proving the Turing Completeness of Fonts:

The goal is:

I wanted to try to implement addition. The input glyph stream would be of the form "=1234+5678=" and the shaping process would turn that string into "6912".

The sheer number of details precludes a simple summary. Mix a little recursion with a strong helping of remapping to implement some grammar productions and voila! The font file is available on Google drive.

What "creative" [mis]applications of this technology can you think of? Define a font file that has a 1:1 mapping of all ASCII characters... except replace all instances of "123" with "456". How could you recognize this had happened to you?

Consider: embedding it in a web page or a PDF document. Making it a new (default) printer font.

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Original Submission

• Re:How is this font used? Re:How is this font used? (Score: 2, Informative) by Anonymous Coward on Thursday March 14 2019, @12:29PM (1 child)

  by Anonymous Coward on Thursday March 14 2019, @12:29PM (#814153)

  You need a hacked harfbuzz and to be using an app using it.

  Parent

  Starting Score:	0		points
  Moderation		+2
  Informative=2, Total=2
  Extra 'Informative' Modifier		0
  Total Score:		2

• Re:How is this font used? (Score: 1, Interesting) by Anonymous Coward on Thursday March 14 2019, @09:01PM

  by Anonymous Coward on Thursday March 14 2019, @09:01PM (#814462)

  So ... then the font isn't turing complete per se. The font is only a syntax for a turing complete language that can be used in specific applications. Seams pretty boring to me.

  Parent