From 81b3985d506e66a8f000d8ae673e80f21eec3e6b Mon Sep 17 00:00:00 2001
From: Ludwig Stecher <ludwig.stecher@gmx.de>
Date: Sat, 21 Dec 2024 21:18:12 +0100
Subject: [PATCH] feat: add help suggestion to disambiguate parsing order with
 intersection

---
 pomsky-lib/src/diagnose/help.rs                            | 5 +++++
 pomsky-lib/tests/testcases/intersections/e_multiple.txt    | 7 +++++++
 .../tests/testcases/intersections/e_string_empty.txt       | 7 +++++++
 .../tests/testcases/intersections/e_string_too_long.txt    | 7 +++++++
 .../tests/testcases/intersections/e_with_assertions.txt    | 7 +++++++
 pomsky-lib/tests/testcases/intersections/strings.txt       | 3 +++
 6 files changed, 36 insertions(+)
 create mode 100644 pomsky-lib/tests/testcases/intersections/e_multiple.txt
 create mode 100644 pomsky-lib/tests/testcases/intersections/e_string_empty.txt
 create mode 100644 pomsky-lib/tests/testcases/intersections/e_string_too_long.txt
 create mode 100644 pomsky-lib/tests/testcases/intersections/e_with_assertions.txt
 create mode 100644 pomsky-lib/tests/testcases/intersections/strings.txt

diff --git a/pomsky-lib/src/diagnose/help.rs b/pomsky-lib/src/diagnose/help.rs
index ed8045a..90ecbbe 100644
--- a/pomsky-lib/src/diagnose/help.rs
+++ b/pomsky-lib/src/diagnose/help.rs
@@ -175,6 +175,11 @@ pub(super) fn get_compiler_help(kind: &CompileErrorKind, _span: Span) -> Option<
                     .to_string(),
             )
         }
+        CompileErrorKind::BadIntersection => Some(
+            "One character sets can be intersected.\n\
+            Parentheses may be required to clarify the parsing order."
+                .to_string(),
+        ),
 
         _ => None,
     }
diff --git a/pomsky-lib/tests/testcases/intersections/e_multiple.txt b/pomsky-lib/tests/testcases/intersections/e_multiple.txt
new file mode 100644
index 0000000..d6c9a29
--- /dev/null
+++ b/pomsky-lib/tests/testcases/intersections/e_multiple.txt
@@ -0,0 +1,7 @@
+#! expect=error
+[w] & [d] [s]
+-----
+ERROR: Intersecting these expressions is not supported. Only character sets can be intersected.
+HELP: One character sets can be intersected.
+Parentheses may be required to clarify the parsing order.
+SPAN: 0..13
\ No newline at end of file
diff --git a/pomsky-lib/tests/testcases/intersections/e_string_empty.txt b/pomsky-lib/tests/testcases/intersections/e_string_empty.txt
new file mode 100644
index 0000000..f108c9f
--- /dev/null
+++ b/pomsky-lib/tests/testcases/intersections/e_string_empty.txt
@@ -0,0 +1,7 @@
+#! expect=error
+'a' & ''
+-----
+ERROR: Intersecting these expressions is not supported. Only character sets can be intersected.
+HELP: One character sets can be intersected.
+Parentheses may be required to clarify the parsing order.
+SPAN: 0..8
\ No newline at end of file
diff --git a/pomsky-lib/tests/testcases/intersections/e_string_too_long.txt b/pomsky-lib/tests/testcases/intersections/e_string_too_long.txt
new file mode 100644
index 0000000..23de708
--- /dev/null
+++ b/pomsky-lib/tests/testcases/intersections/e_string_too_long.txt
@@ -0,0 +1,7 @@
+#! expect=error
+[w] & 'ab'
+-----
+ERROR: Intersecting these expressions is not supported. Only character sets can be intersected.
+HELP: One character sets can be intersected.
+Parentheses may be required to clarify the parsing order.
+SPAN: 0..10
\ No newline at end of file
diff --git a/pomsky-lib/tests/testcases/intersections/e_with_assertions.txt b/pomsky-lib/tests/testcases/intersections/e_with_assertions.txt
new file mode 100644
index 0000000..03bbe92
--- /dev/null
+++ b/pomsky-lib/tests/testcases/intersections/e_with_assertions.txt
@@ -0,0 +1,7 @@
+#! expect=error
+'a' & 'b' $
+-----
+ERROR: Intersecting these expressions is not supported. Only character sets can be intersected.
+HELP: One character sets can be intersected.
+Parentheses may be required to clarify the parsing order.
+SPAN: 0..11
\ No newline at end of file
diff --git a/pomsky-lib/tests/testcases/intersections/strings.txt b/pomsky-lib/tests/testcases/intersections/strings.txt
new file mode 100644
index 0000000..af34248
--- /dev/null
+++ b/pomsky-lib/tests/testcases/intersections/strings.txt
@@ -0,0 +1,3 @@
+'a' & 'b'
+-----
+[a&&b]
\ No newline at end of file