Parser

Represents where a failure occurred and all the expectations that were broken

An expectation reports the kind or parsing error and where it occured.

If we can parse this then that, do so, if we fail that without consuming, rewind before this without consuming. If either consume 1 or more, do not rewind

If we can parse this then that, do so, if we fail that without consuming, rewind before this without consuming. If either consume 1 or more, do not rewind

If we can parse this then that, do so, if we fail that without consuming, rewind before this without consuming. If either consume 1 or more, do not rewind

Enables syntax to access product01, product and flatMap01 This helps us build Parser instances when starting from a Parser0

The names of the product elements

The name of the type

Parse 1 character from the string

Replaces parsed values with the given value.

Replaces parsed values with the given value.

If we fail, rewind the offset back so that we can try other branches. This tends to harm debuggability and ideally should be minimized

If we fail, rewind the offset back so that we can try other branches. This tends to harm debuggability and ideally should be minimized

parse a single character

An empty iterable is the same as fail

parse one of a given set of characters

parse one character that matches a given function

Parse a string while the given function is true parses at least one character

Parse a string while the given function is true

Lazily create a Parser This is useful to create some recursive parsers see Defer0[Parser].fix

Lazily create a Parser0 This is useful to create some recursive parsers see Defer0[Parser].fix

If the first parser fails to parse its input with an epsilon error, try the second parser instead.

If the first parser fails with an arresting error, the second parser won't be tried.

Backtracking may be used on the first parser to allow the second one to pick up after any error, resetting any state that was modified by the first parser.

If the first parser fails to parse its input with an epsilon error, try the second parser instead.

If the first parser fails with an arresting error, the second parser won't be tried.

Backtracking may be used on the first parser to allow the second one to pick up after any error, resetting any state that was modified by the first parser.

succeeds when we are at the end

A parser that always fails with an epsilon failure

A parser that always fails with an epsilon failure and a given message this is generally used with flatMap to validate a result beyond the literal parsing.

e.g. parsing a number then validate that it is bounded.

Standard monadic flatMap Avoid this function if possible. If you can instead use product, ~, >, or < use that. flatMap always has to allocate a parser, and the parser is less amenable to optimization

Standard monadic flatMap where you end with a Parser Avoid this function if possible. If you can instead use product, ~, >, or < use that. flatMap always has to allocate a parser, and the parser is less amenable to optimization

Standard monadic flatMap where you start with a Parser Avoid this function if possible. If you can instead use product, ~, >, or < use that. flatMap always has to allocate a parser, and the parser is less amenable to optimization

Parse a given string, in a case-insensitive manner, or fail. This backtracks on failure this is an error if the string is empty

Parse a potentially empty string, in a case-insensitive manner, or fail. This backtracks on failure

Ignore the case of a single character If you want to know if it is upper or lower, use .string to capture the string and then map to process the result.

Parse any single character in a set of characters as lower or upper case

Parse any single character in a set of characters as lower or upper case

return the current position in the string we are parsing. This lets you record position information in your ASTs you are parsing

Parse the next len characters where len > 0 if (len < 1) throw IllegalArgumentException

if len < 1, the same as pure("") else length(len)

transform a Parser result

transform a Parser0 result

returns a parser that succeeds if the current parser fails. Note, this parser backtracks (never returns an arresting failure)

go through the list of parsers trying each as long as they are epsilon failures (don't advance) see @backtrack if you want to do backtracking.

This is the same as parsers.foldLeft(fail)(.orElse())

recommended style: oneOf(p1 :: p2 :: p3 :: Nil) rather than oneOf(List(p1, p2, p3))

Note: order matters here, since we don't backtrack by default.

go through the list of parsers trying each as long as they are epsilon failures (don't advance) see @backtrack if you want to do backtracking.

This is the same as parsers.foldLeft(fail)(.orElse())

recommended style: oneOf(p1 :: p2 :: p3 :: Nil) rather than oneOf(List(p1, p2, p3))

Note: order matters here, since we don't backtrack by default.

a parser that consumes nothing when it succeeds, basically rewind on success

parse first then second

product with the second argument being a Parser

product with the first argument being a Parser

Don't advance in the parsed string, just return a This is used by the Applicative typeclass.

Build a recursive parser by assuming you have it Useful for parsing recurive structures, like for instance JSON.

Repeat the parser min or more times

The parser fails if it can't match at least min times

Repeat the parser min or more times, but no more than max

The parser fails if it can't match at least min times After repeating the parser max times, the parser completes succesfully

Repeat the parser 0 or more times

Repeat the parser 0 or more times, but no more than max

It may seem weird to accept 0 here, but without, composing this method becomes more complex. Since and empty parse is possible for this method, we do allow max = 0

Repeat the parser exactly times times

Repeat 1 or more times with a separator

Repeat min or more times with a separator, at least once.

Repeat min or more, up to max times with a separator, at least once.

Repeat 0 or more times with a separator

Repeat min or more times with a separator.

Repeat min or more, up to max times with a separator.

parse one or more times until Parser end succeeds.

parse zero or more times until Parser end succeeds.

parse one or more times until Parser end succeeds.

parse zero or more times until Parser end succeeds.

Parser version of select

Parse p and if we get the Left side, parse fn This function name comes from seletive functors. This should be more efficient than flatMap since the fn Parser0 is evaluated once, not on every item parsed

softProduct, a variant of product A soft product backtracks if the first succeeds and the second is an epsilon-failure. By contrast product will be a failure in that case

see @Parser.soft

softProduct with the second argument being a Parser A soft product backtracks if the first succeeds and the second is an epsilon-failure. By contrast product will be a failure in that case

see @Parser.soft

softProduct with the first argument being a Parser A soft product backtracks if the first succeeds and the second is an epsilon-failure. By contrast product will be a failure in that case

see @Parser.soft

succeeds when we are at the start

Parse a given string or fail. This backtracks on failure this is an error if the string is empty

Discard the result A and instead capture the matching string this is optimized to avoid internal allocations

Parse a potentially empty string or fail. This backtracks on failure

Discard the result A and instead capture the matching string this is optimized to avoid internal allocations

Parse the longest matching string between alternatives. The order of the strings does not matter.

If no string matches, this parser results in an epsilon failure.

It is an error to pass the empty string here, if you need that see stringIn0

Version of stringIn that allows the empty string

tail recursive monadic flatMaps on Parser This is a rarely used function, but needed to implement cats.FlatMap Avoid this function if possible. If you can instead use product, ~, >, or < use that. flatMap always has to allocate a parser, and the parser is less amenable to optimization

tail recursive monadic flatMaps This is a rarely used function, but needed to implement cats.FlatMap Avoid this function if possible. If you can instead use product, ~, >, or < use that. flatMap always has to allocate a parser, and the parser is less amenable to optimization

parse one or more characters as long as they don't match p

parse zero or more characters as long as they don't match p this is useful for parsing comment strings, for instance.

discard the value in a Parser. This is an optimization because we remove trailing map operations and don't allocate internal data structures This function is called internal to Functor.as and Apply.> and Apply.< so those are good uses.

discard the value in a Parser. This is an optimization because we remove trailing map operations and don't allocate internal data structures This function is called internal to Functor.as and Apply.> and Apply.< so those are good uses.

Add a context string to Errors to aid debugging

Add a context string to Errors to aid debugging

A parser that always fails with an epsilon failure

A parser that returns unit