From Test-Scratch-Wiki
This documentation is transcluded from Template:Error/doc.
This is used when making templates that print out errors similar to parser function error.
{{#expr:2+2}}→ 4{{#expr:10/0}}→Division by zero.{{#expr:what}}→ Expression error: Unrecognized word "what".{{error|You have an error.}}→ You have an error.
{{#expr:123*456-78+9/0^12}}→ Division by zero.{{error|Division by zero.}}→ Division by zero.
