Dyalog version 18.0, released in June 2020, introduced the Case Convert system function ⎕C. It was a replacement for the long-lived (since version 15.0, from June 2016) I-beam 819⌶, which was then deprecated. (By the way, did you know that the digits 819 were chosen to be reminiscent of the letters BIg as in big — uppercase — letters?) It is expected that 819⌶ will be disabled in the next major version of Dyalog APL.

⎕C already has several advantages over 819⌶, for example the ability to case-fold rather than lowercase. (Did you know that Cherokee syllabary case-folds to uppercase?) With today’s release of Dyalog version 19.4.1, we’re happy to announce a further extension of ⎕C, covering scaled format (also known as scientific or E notation) and complex numbers.

By default, APL uses the letter E to separate mantissa and exponent in very large and very small numbers. Similarly, the letter J is used to separate real and imaginary parts of complex numbers:

      2 20 * 64 ¯24
1.844674407E19 5.960464478E¯32
      ¯1 ¯5*0.5
0J1 0J2.236067977

For input, however, e and j are accepted in addition to E and J:

      1E4 1J4 ≡ 1e4 1j4
1

You can now conveniently mitigate this asymmetry using ⎕C:

      ⎕C 2 20 * 64 ¯24
1.844674407e19 5.960464478e¯32
      ⎕C ¯1 ¯5 * 0.5
0j1 0j2.236067977

We hope that this added functionality will be exploited to its fullest by all our users. Please contact us if you experience any stability issues with the new feature.

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