The monad type.

A scanner that never produces any value.

A scanner that returns true at the end of the input sequence, otherwise returns false.

The abstract type representing a resumption point in the input.

A scanner that produces a mark captured at the current position.

Use mov mark to resume scanning at the captured mark.

Use pos mark to make a unit value attributed with the position of captured mark. If the mark was captured at the end of the stream, then the result is an implicit form.

The universal symbol scanner. Recognizes any symbol in the input stream and produces its form. Does not produce anything at the end of input.

The literal symbol scanner. Use one symbol to make a scanner that recognizes symbol in the input stream and produces its form.

The symbol satisfier scanner. Use sat f to make a scanner that recognizes any symbol for which applying f returns true and produces its form.

The ignore scanner. Use ign f to make a scanner that scans the input while applying f to each symbol returns true, then produces a unit form that annotates the span of ignored symbols. Produces an implicit unit form if the end of input has already been reached.

The symbolic token scanner. Use tok f to make a scanner that recognizes any symbol for which applying f returns Some v, then produces the form of v.

The opaque value form scanner composer. Use ntyp n p to make a scanner that encloses the value contained in the form produced by p in an opaque value with the runtime type indicated by n and returns its form in the same position.

The default value scanner. Use dflt v p to produce the output of p or the default value v with implicit annotation if p does not produce output.

The optional scanner composer. Use opt p to make a scanner that produces either Some v if p produces v otherwise None.

The visitor scanner composer. Use vis ?a ?b f v to compose a scanner that recognizes a sequence of elements in the input stream by applying a visitor function f at each element to obtain its scanner. The first element is visited with the initializer v, and each following element is visited with the value returned by the preceding scanner.

If ~a is used, then it specifies the minimum number of elements to visit. If ~b is used then it specifies the maximum number of elements to visit. Composition raises Invalid_argument if a < 0 or b < a.

The homogenous list scanner composer. Use seq ?a ?b p to create a new scanner that uses p to recognize and produce, in order, each element in a sequence of elements in the input stream.

If ~a is used, then it specifies the minimum number of elements that must be recognized and produced in the output. If ~b is used then it specifies the maximum number of elements to recognize. Composition raises Invalid_argument if a < 0 or b < a.

The bounded multiple choice scanner. Use alt ps to create a scanner that produces the output from the first scanner ps that produces. If no scanner in ps produces output, then the resulting scanner does not produce.

The unbounded multiple choice scanner. Use alt ps to create a scanner that produces the output from the first scanner ps that produces. If no scanner in ps produces output, then the resulting scanner does not produce.

A distinguished syntax failure exception.

Use fail msg to raise Bad_syntax with msg optionally annotated with the current position.

Use or_fail msg p to make a scanner that raises Bad_syntax with msg if p does not recognize its input. It may be convenient to call this function with a pipeline operator, i.e. p |> or_fail "reasons".

Use err ~x () to make a scanner that raises x. If ?x is not provided, then it raises Not_found.

Use errf ~xf () to make a scanner that captures a mark and applies it to xf to raise an exception. If ?xf is not provided, then raises Not_found.

Use req ~x p to make a scanner that either produces the output of p or raises x. If p does not produce and ?x is not provided, then it raises Not_found.

Use reqf ~xf p to make a scanner that either produces the output of p or captures a mark at the current input and applies it to xf to raise an exception. If ?xf is not provided, then raises Not_found.

The conversion scanner. Use cast f p to create a scanner produces the result of applying f to the value recognized by p. If f raises Not_found then the resulting scanner does not produce. If f raises Failure s then it will be caught and Bad_syntax will be raised with the corresponding message decorated with the position.

The error check scanner. Use ck p to create a new scanner that either produces either Ok v if p produces v or Error x if scanning the input with p raises the exception x.

The error recovery scanner. Use sync p to scan the input with p until it produces or reaches the end of input. Produces Some v if p ever produces v, otherwise produces None if the end of input is reached without p producing a value.

Use lift p s to map s into a persistent sequence of the values produced by p. If ~start is provided, then it specifies the starting position of the first symbol in s.

Use of_seq p s to parse s with p and return the result. Raises Not_found if p does not recognize the entire sequence of s. If ~start is provided, then it specifies the starting position of the first symbol in s.

Combinator operators