Class TemplateExpressionParser

The MJ Query expression grammar, a small recursive-descent parser:

expression := or ["if" or ["else" or]]          (inline if: body if condition else otherwise)
or         := and ("or" and)*
and        := not ("and" not)*
not        := "not" not | compare
compare    := additive (("==" | "!=" | "<" | ">" | "<=" | ">=") additive)*
additive   := term (("+" | "-") term)*
term       := unary (("*" | "/" | "%") unary)*
unary      := ("-" | "+") unary | postfix, then filters ("|" name ["(" args ")"])*
postfix    := primary ("." name | "(" args ")" | "[" expression "]")*
primary    := name | number | string | true | false | null | "(" expression ")"
Copy

Filters bind tighter than every binary operator, and every binary operator tighter than the inline if, as in Nunjucks: x | sqlNumber if x else 12 is (x | sqlNumber) if x else 12. Of the postfix forms only Context.<Token>, loop.<member> and <name>.length are in the language. Constructs outside the grammar parse into Unsupported nodes with a diagnostic; parsing never throws.