Make use of -- operator a syntax error
#9561
Conversation
Pending decision on issue #9532
jakebolewski
force-pushed
the
jcb/decsyntaxerr
branch
from
7c0bfe9
to
ee08134
Compare
|
+1, but if we go with this, we should have an answer to why this is a change that doesn't need a depreciation period. |
| @@ -8,7 +8,7 @@ | |||
| (define prec-conditional '(?)) | |||
| (define prec-lazy-or '(|\|\||)) | |||
| (define prec-lazy-and '(&&)) | |||
| (define prec-arrow '(-- --> ← → ↔ ↚ ↛ ↠ ↣ ↦ ↮ ⇎ ⇏ ⇒ ⇔ ⇴ ⇶ ⇷ ⇸ ⇹ ⇺ ⇻ ⇼ ⇽ ⇾ ⇿ ⟵ ⟶ ⟷ ⟷ ⟹ ⟺ ⟻ ⟼ ⟽ ⟾ ⟿ ⤀ ⤁ ⤂ ⤃ ⤄ ⤅ ⤆ ⤇ ⤌ ⤍ ⤎ ⤏ ⤐ ⤑ ⤔ ⤕ ⤖ ⤗ ⤘ ⤝ ⤞ ⤟ ⤠ ⥄ ⥅ ⥆ ⥇ ⥈ ⥊ ⥋ ⥎ ⥐ ⥒ ⥓ ⥖ ⥗ ⥚ ⥛ ⥞ ⥟ ⥢ ⥤ ⥦ ⥧ ⥨ ⥩ ⥪ ⥫ ⥬ ⥭ ⥰ ⧴ ⬱ ⬰ ⬲ ⬳ ⬴ ⬵ ⬶ ⬷ ⬸ ⬹ ⬺ ⬻ ⬼ ⬽ ⬾ ⬿ ⭀ ⭁ ⭂ ⭃ ⭄ ⭇ ⭈ ⭉ ⭊ ⭋ ⭌ ￩ ￫)) | |||
| (define prec-arrow '(--> ← → ↔ ↚ ↛ ↠ ↣ ↦ ↮ ⇎ ⇏ ⇒ ⇔ ⇴ ⇶ ⇷ ⇸ ⇹ ⇺ ⇻ ⇼ ⇽ ⇾ ⇿ ⟵ ⟶ ⟷ ⟷ ⟹ ⟺ ⟻ ⟼ ⟽ ⟾ ⟿ ⤀ ⤁ ⤂ ⤃ ⤄ ⤅ ⤆ ⤇ ⤌ ⤍ ⤎ ⤏ ⤐ ⤑ ⤔ ⤕ ⤖ ⤗ ⤘ ⤝ ⤞ ⤟ ⤠ ⥄ ⥅ ⥆ ⥇ ⥈ ⥊ ⥋ ⥎ ⥐ ⥒ ⥓ ⥖ ⥗ ⥚ ⥛ ⥞ ⥟ ⥢ ⥤ ⥦ ⥧ ⥨ ⥩ ⥪ ⥫ ⥬ ⥭ ⥰ ⧴ ⬱ ⬰ ⬲ ⬳ ⬴ ⬵ ⬶ ⬷ ⬸ ⬹ ⬺ ⬻ ⬼ ⬽ ⬾ ⬿ ⭀ ⭁ ⭂ ⭃ ⭄ ⭇ ⭈ ⭉ ⭊ ⭋ ⭌ ￩ ￫)) | |||
There was a problem hiding this comment.
was it a typo in the first place, should it maybe have been <-- to start with?
There was a problem hiding this comment.
Nevermind. Tracing this through the history it goes way back - 6e515e7#diff-1
-> and <- were once parsed as operators, but <-- never was. Does the comment
note: there are some strange-looking things in here because
the way the lexer works, every prefix of an operator must also
be an operator.
mean this change would break parsing of --> as an operator? That is likely not tested...
There was a problem hiding this comment.
This does break --> but only because you can't peek ahead 2-characters. Making this work would be a bit hacky, maybe we should just allow them and go with @StefanKarpinski's suggestion which I think is a good one.
|
There is another way to make this a syntax error. We can leave it in the operator tables, but raise an error if it actually occurs not as part of |
|
Also, nobody has used this as an operator as far as I know, but it would be fine to deprecate it. |
|
I think the unicode replacements are probably satisfactory in place of |
|
Leaving it in the operator table but raising an error anyway seemed a bit hacky to me. Could we just remove |
Pending decision on issue #9532