Grammar Reference Overview

This directory describes lexical tokens and grammatical structure in Norm source. The notation is close to EBNF; the first compiler implementation needs to make every production a machine-testable grammar.

Notation

"token"      fixed keyword or symbol
Name         another production
A?           optional
A*           zero or more
A+           one or more
A | B        either choice

Source files

SourceFile := (AnnotationUse* PackageDeclaration)? Import* Declaration*

A package appears at the start of the file; imports precede other declarations. A file without a package is a single-file script. Top-level source permits types, functions, and compile-time constants, but not arbitrary execution statements. module.norm in a module's root package directory uses the same SourceFile syntax and produces a module definition through Module module().

Declarations

Declaration := ClassDeclaration
             | ValueDeclaration
             | InterfaceDeclaration
             | EnumDeclaration
             | AnnotationDeclaration
             | FunctionDeclaration

Norm puts types first: String name, Integer parse(String text). Generic parameters follow the declared name; the nullable marker follows the complete type.

Expressions and statements

Literals, names, member access, calls, indexing, operators, and control expressions produce values. Variable declarations, assignment, return, and throw are statements. In a value position, if, for, and switch explicitly produce a result through break value.

Related sections

• Lexical rules
• Declarations
• Types
• Expressions
• Statements
• Module configuration
• Operator precedence
• ref<T> references
• Declaration references and reflection