Syntax

Note

This page is under construction.

Like Lua and most C-family programming languages:

• Code blocks begin with { and end with }
• Line comments begin with // and end with a newline
• Block comments begin with /* and end with */ (and cannot be nested)
• All whitespace is equivalent, used to separate tokens, with the following exceptions:
  • Strings, where whitespace is interpreted literally
  • Line comments, where only a newline ends a line comment

Unless you really care about formalism, you’re better off reading the examples to get a jist of the syntax.

Tokens

The file is split into tokens, where each token is one of the following:

• Line comment beginning with // and ending with the next newline
• Block comment beginning with /* and ending with the next */
• String beginning and ending with " (may contain any character except ")
• String beginning and ending with ' (may contain any character except ')
• Number with a decimal point, matching the regex -?\d?\.\d+ (currently unused)
• Number without a decimal point, matching the regex -?\d+
• Keyword (see Keywords)
• Identifier, matching the regex [A-Za-z_][A-Za-z_\d]*
• Tag name, consisting of # followed immediately by an identifier (no space)
• Directive name, consisting of @ followed immediately by an identifier (no space)
• One of the following literal character sequences:
  • Assignment operator +=, -=, *=, /=, %=, &=, |=, ^=, **=, <<=, >>=, or >>>=
  • Operator .., **, <<, >>, or >>>
  • Relational operator ==, !=, <=, or >=
• Any other single Unicode character from the letter, numeral, punctuation, or symbol categories. (See Unicode Character Categories.)

Note that newlines are allowed in strings.

NOTE: string syntax may change in the future

NOTE: either document and use string prefix characters, or remove support for them from the lexer

Keywords

The following keywords are reserved, and cannot be used for identifiers:

• and
• assert
• become
• bind
• bound
• break
• case
• colors
• continue
• else
• error
• for
• icons
• if
• in
• is
• match
• models
• not
• or
• remain
• return
• same
• static
• transition
• unless
• where
• while
• with
• xor

Some of these are currently used, and some are reserved for future use.

File structure

An NDCA file consists of a sequence of directives.

Directives

Directives begin with a directive name, which always begins with @, followed by an expression, code block, or other construct depending on the specific directive. See Directives for more.

Code blocks

A code block begins with a single {, contains zero or more statements, and ends with a single }. Statements are not separated by a semicolon. Although it is conventional for each statement to be placed on its own line, this is optional; newlines can be inserted anywhere or omitted completely.