From b9ad22734b0d27709f6733d3d12a831ea28bc82c Mon Sep 17 00:00:00 2001 From: Marshall Lochbaum Date: Tue, 18 May 2021 22:11:16 -0400 Subject: History of Assert (!) --- docs/commentary/history.html | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'docs/commentary') diff --git a/docs/commentary/history.html b/docs/commentary/history.html index 1e4e2aab..8b93d2f9 100644 --- a/docs/commentary/history.html +++ b/docs/commentary/history.html @@ -130,6 +130,13 @@ + + +Rogers +Assert primitive ! + + + -05 ngn/apl Nikolov @@ -205,6 +212,8 @@

I picked out the ligature character ‿ between YAG meetings, but I think Richard Park was most responsible for the idea of a "shortcut" list notation.

Double-struck special names

There was a lot of discussion about names for arguments at YAG (no one liked alpha and omega); I think Nathan Rogers suggested using Unicode's mathematical variants of latin letters and I picked out the double-struck ones. My impression is that we were approaching a general concensus that "w" and "x" were the best of several bad choices of argument letters, but that I was the first to commit to them.

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Assert primitive

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Nathan Rogers suggested that assertion should be made a primitive to elevate it to a basic part of the language. I used J's assert often enough for this idea to make sense immediately, but I think it was new to me. He suggested the dagger character; I changed this to the somewhat similar-looking !. The error-trapping modifier ⎊ is identical to J's ::, but J only has the function [: to unconditionally throw an error, with no way to set a message.

Context-free grammar

In YAG meetings, I suggested adopting APL\iv's convention that variable case must match variable type in order to achieve a context-free grammar. Adám, a proponent of case-insensitive names, pointed out that the case might indicate the type the programmer wanted to use instead of the value's type, creating cross roles.

Headers

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