parse unicode forall and exists as identifiers

NEWS.md

@@ -12,6 +12,7 @@ New language features
  to enforce the involved function calls to be (or not to be) inlined. ([#41312])
 * The default behavior of observing `@inbounds` declarations is now an option via `auto` in `--check-bounds=yes|no|auto` ([#41551])
 * New function `eachsplit(str)` for iteratively performing `split(str)`.
+* `∀`, `∃`, and `∄` are now allowed as identifier characters ([#42314]).
 
 Language changes
 ----------------

src/flisp/julia_extensions.c

@@ -82,9 +82,10 @@ static int is_wc_cat_id_start(uint32_t wc, utf8proc_category_t cat)
  wc == 0x223f || wc == 0x22be || wc == 0x22bf || // ∿, ⊾, ⊿
  wc == 0x22a4 || wc == 0x22a5 || // ⊤ ⊥
 
- (wc >= 0x2202 && wc <= 0x2233 &&
+ (wc >= 0x2200 && wc <= 0x2233 &&
  (wc == 0x2202 || wc == 0x2205 || wc == 0x2206 || // ∂, ∅, ∆
  wc == 0x2207 || wc == 0x220e || wc == 0x220f || // ∇, ∎, ∏
+ wc == 0x2200 || wc == 0x2203 || wc == 0x2204 || // ∀, ∃, ∄
  wc == 0x2210 || wc == 0x2211 || // ∐, ∑
  wc == 0x221e || wc == 0x221f || // ∞, ∟
  wc >= 0x222b)) || // ∫, ∬, ∭, ∮, ∯, ∰, ∱, ∲, ∳

test/syntax.jl

@@ -2967,6 +2967,12 @@ end
 @generated g25678(x) = return :x
 @test g25678(7) === 7
 
+# issue #19012
+@test Meta.parse("\U2200", raise=false) == Symbol("∀")
+@test Meta.parse("\U2203", raise=false) == Symbol("∃")
+@test Meta.parse("a\U2203", raise=false) == Symbol("a∃")
+@test Meta.parse("\U2204", raise=false) == Symbol("∄")
+
 # issue 42220
 macro m42220()
  return quote