Module expr

Structs

All

A [Step] that consumes a list of expressions and only matches if all the child Exprs do.

AnchorEnd

A Step which will match only if the cursor is over the last non-whitespace character in stream. It will return that token.

AnchorStart

A Step which will match only if the cursor is over the first word-like of a token stream. It will return that token.

ExprMap

A map from an Expr to arbitrary data.

FixedPhrase

Matches a fixed sequence of tokens as they appear in the input. Case-insensitive for words but maintains exact matching for other token types.

LongestMatchOf

A [Step] that returns the farthest offset of the longest match in a list of expressions.

MergeableWords

A Expr that identifies adjacent words that could potentially be merged into a single word.

Repeating

An expression that will match one or more repetitions of the same expression.

SequenceExpr

SimilarToPhrase

SpelledNumberExpr

Matches spelled-out numbers from one to ninety-nine

TimeUnitExpr

Matches a time unit.

UnlessStep

Provides the ability to use an expression as a condition. If the condition does not match, it will return the result of the provided step.

WordExprGroup

An expression collection to look for expressions that start with a specific word.

Traits

Expr

A common problem in Harper is that we need to identify tokens that fulfil certain criterion. An Expr is a way to express whether a certain set of tokens fulfil that criteria. When supplied a specific position in a token stream, the job of an Expr is to determine the window of tokens (including the cursor itself) that fulfils whatever criteria the author desires. It is then the job of another system to identify portions of documents that fulfil this criteria.

ExprExt

OwnedExprExt

Step

An atomic step within a larger expression.