History of Assert (!)

1 files changed, 5 insertions, 0 deletions

diff --git a/commentary/history.md b/commentary/history.md
index 5963d19f..5e8e172a 100644
--- a/commentary/history.md
+++ b/commentary/history.md
@@ -35,6 +35,7 @@ The table documents when I encountered features or interesting decisions in BQN.
 |      |        | Brudzewsky | Cross-roles
 |      |        | w/ Park? | Ligature `‿`
 |      |        | w/ Rogers | Double-struck special names
+|      |        | Rogers | Assert primitive `!`
 |  -05 | [ngn/apl](https://aplwiki.com/wiki/Ngn/apl) | Nikolov | Multiple function bodies `;`
 |  -06 | BQN    | | Group (`⊔`) | [0](https://chat.stackexchange.com/transcript/52405?m=54600976#54600976), [1](https://chat.stackexchange.com/transcript/message/55456874#55456874)
 |      | | | Nothing (`·`) | [0](https://chat.stackexchange.com/transcript/message/54703617#54703617)
@@ -67,6 +68,10 @@ I picked out the ligature character `‿` between YAG meetings, but I think Rich
 
 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.
 
+#### Assert primitive
+
+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](https://aplwiki.com/wiki/APL%5Civ)'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.