roc/test/fx/string_pattern_matching.roc
Richard Feldman cc3423a709
Implement ? (question mark) operator for error propagation
The ? operator now desugars expr? to a match expression that unwraps Ok
values and early returns Err values:

  match expr {
      Ok(#ok) => #ok,
      Err(#err) => return Err(#err),
  }

Implementation details:
- Use pre-interned identifiers (#ok, #err) for synthetic variables
- Use pre-interned Ok/Err tag names from CommonIdents
- Create applied_tag patterns for Ok and Err
- Build match branches with proper scope isolation
- Mark synthetic patterns as used to avoid unused variable warnings
- Create e_lookup_local, e_tag, and e_return expressions for branch bodies

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>
2025-11-29 20:06:33 -05:00

19 lines
360 B
Text

app [main!] { pf: platform "./platform/main.roc" }
import pf.Stdout
# Tests pattern matching on string literals in match expressions.
main! = || {
greet("Alice")
greet("Bob")
}
greet = |name| {
message = match name {
"Alice" => "Hello Alice!"
"Bob" => "Hey Bob!"
_ => "Hello stranger!"
}
Stdout.line!(message)
}