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Context-Free Syntax

The context-free syntax describes the more high-level syntactic structure of sentences in a language. A context-free syntax contains a list of productions. Elements of the right-hand side of a context-free production are pre-processed in a normalization step before parser generation that adds the LAYOUT? symbol between any two symbols.

Context-free syntax has the form:

context-free syntax

  $Production*

An example production rule:

context-free syntax

  Block.Block = "{" Statement* "}"

SDF3 automatically allows for layout to be present between the symbols of a rule. This means that a fragment such as:

{

}

will still be recognized as a block (assuming that the newline and line-feed characters are defined as layout).


Last update: 2021-11-15
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