| Type: | Package |
| Title: | Parser Combinator for R |
| Version: | 0.1.1 |
| Date: | 2016-10-23 |
| Author: | Chapman Siu |
| Maintainer: | Chapman Siu <chpmn.siu@gmail.com> |
| Description: | Parser generator for R using combinatory parsers. It is inspired by combinatory parsers developed in Haskell. |
| License: | MIT + file LICENSE |
| Imports: | methods |
| Suggests: | testthat, knitr, rmarkdown |
| VignetteBuilder: | knitr |
| LazyData: | true |
| RoxygenNote: | 5.0.1 |
| URL: | https://github.com/chappers/Ramble |
| NeedsCompilation: | no |
| Packaged: | 2016-10-28 23:40:08 UTC; chapm |
| Repository: | CRAN |
| Date/Publication: | 2016-10-29 10:48:13 |
Ramble is a parser generator using combinatory parsers.
Description
Ramble allows you to write parsers in a functional manner, inspired by Haskell's Parsec library.
%alt% is the infix notation for the alt function.
Description
%alt% is the infix notation for the alt function.
Usage
p1 %alt% p2
Arguments
p1 |
the first parser |
p2 |
the second parser |
Value
Returns the first parser if it suceeds otherwise the second parser
Examples
(item() %alt% succeed("2")) ("abcdef")
%then% is the infix operator for the then combinator.
Description
%then% is the infix operator for the then combinator.
Usage
p1 %then% p2
Arguments
p1 |
the first parser |
p2 |
the second parser |
Value
recognises anything that p1 and p2 would if placed in succession.
Examples
(item() %then% succeed("123")) ("abc")
%thentree% is the infix operator for the then combinator, and it is
the preferred way to use the thentree operator.
Description
%thentree% is the infix operator for the then combinator, and it is
the preferred way to use the thentree operator.
Usage
p1 %thentree% p2
Arguments
p1 |
the first parser |
p2 |
the second parser |
Value
recognises anything that p1 and p2 would if placed in
succession.
See Also
Examples
(item() %thentree% succeed("123")) ("abc")
%using% is the infix operator for using
Description
%using% is the infix operator for using
Usage
p %using% f
Arguments
p |
is the parser to be applied |
f |
is the function to be applied to each result of |
Examples
(item() %using% as.numeric) ("1abc")
Alpha checks for single alphabet character
Description
Alpha checks for single alphabet character
Usage
Alpha(...)
Arguments
... |
additional arguments for the primitives to be parsed |
See Also
Digit, Lower, Upper,
AlphaNum, SpaceCheck,
String, ident, nat,
space, token, identifier,
natural, symbol
Examples
Alpha()("abc")
AlphaNum checks for a single alphanumeric character
Description
AlphaNum checks for a single alphanumeric character
Usage
AlphaNum(...)
Arguments
... |
additional arguments for the primitives to be parsed |
See Also
Digit, Lower, Upper,
Alpha, SpaceCheck,
String, ident, nat,
space, token, identifier,
natural, symbol
Examples
AlphaNum()("123")
AlphaNum()("abc123")
Digit checks for single digit
Description
Digit checks for single digit
Usage
Digit(...)
Arguments
... |
additional arguments for the primitives to be parsed |
See Also
Lower, Upper,
Alpha, AlphaNum, SpaceCheck,
String, ident, nat,
space, token, identifier,
natural, symbol
Examples
Digit()("123")
Lower checks for single lower case character
Description
Lower checks for single lower case character
Usage
Lower(...)
Arguments
... |
additional arguments for the primitives to be parsed |
See Also
Digit, Upper,
Alpha, AlphaNum, SpaceCheck,
String, ident, nat,
space, token, identifier,
natural, symbol
Examples
Lower() ("abc")
SpaceCheck checks for a single space character
Description
SpaceCheck checks for a single space character
Usage
SpaceCheck(...)
Arguments
... |
additional arguments for the primitives to be parsed |
See Also
Digit, Lower, Upper,
Alpha, AlphaNum,
String, ident, nat,
space, token, identifier,
natural, symbol
Examples
SpaceCheck()(" 123")
String is a combinator which allows us to build parsers which
recognise strings of symbols, rather than just single symbols
Description
String is a combinator which allows us to build parsers which
recognise strings of symbols, rather than just single symbols
Usage
String(string)
Arguments
string |
is the string to be matched |
See Also
Digit, Lower, Upper,
Alpha, AlphaNum, SpaceCheck,
ident, nat,
space, token, identifier,
natural, symbol
Examples
String("123")("123 abc")
Unlist is the same as unlist, but doesn't recurse all the way to preserve the type. This function is not well optimised.
Description
Unlist is the same as unlist, but doesn't recurse all the way to preserve the type. This function is not well optimised.
Usage
Unlist(obj)
Arguments
obj |
is a list to be flatten |
Upper checks for a single upper case character
Description
Upper checks for a single upper case character
Usage
Upper(...)
Arguments
... |
additional arguments for the primitives to be parsed |
See Also
Digit, Lower,
Alpha, AlphaNum, SpaceCheck,
String, ident, nat,
space, token, identifier,
natural, symbol
Examples
Upper()("Abc")
alt combinator is similar to alternation in BNF. the parser
(alt(p1, p2)) recognises anything that p1 or p2 would.
The approach taken in this parser follows (Fairbairn86), in which either is
interpretted in a sequential (or exclusive) manner, returning the result of
the first parser to succeed, and failure if neither does.
Description
%alt% is the infix notation for the alt function, and it is the
preferred way to use the alt operator.
Usage
alt(p1, p2)
Arguments
p1 |
the first parser |
p2 |
the second parser |
Value
Returns the first parser if it suceeds otherwise the second parser
See Also
Examples
(item() %alt% succeed("2")) ("abcdef")
ident is a parser which matches zero or more alphanumeric
characters.
Description
ident is a parser which matches zero or more alphanumeric
characters.
Usage
ident()
See Also
Digit, Lower, Upper,
Alpha, AlphaNum, SpaceCheck,
String, nat,
space, token, identifier,
natural, symbol
Examples
ident() ("variable1 = 123")
identifier creates an identifier
Description
identifier creates an identifier
Usage
identifier(...)
Arguments
... |
takes in token primitives |
See Also
Digit, Lower, Upper,
Alpha, AlphaNum, SpaceCheck,
String, ident, nat,
space, token,
natural, symbol
item is a parser that consumes the first character of the string and
returns the rest. If it cannot consume a single character from the string, it
will emit the empty list, indicating the parser has failed.
Description
item is a parser that consumes the first character of the string and
returns the rest. If it cannot consume a single character from the string, it
will emit the empty list, indicating the parser has failed.
Usage
item(...)
Arguments
... |
additional arguments for the parser |
Examples
item() ("abc")
item() ("")
literal is a parser for single symbols. It will attempt to match the
single symbol with the first character in the string.
Description
literal is a parser for single symbols. It will attempt to match the
single symbol with the first character in the string.
Usage
literal(char)
Arguments
char |
is the character to be matched |
Examples
literal("a") ("abc")
many matches 0 or more of pattern p. In BNF notation,
repetition occurs often enough to merit its own abbreviation. When zero or
more repetitions of a phrase p are admissible, we simply write
p*. The many combinator corresponds directly to this operator,
and is defined in much the same way.
Description
This implementation of many differs from (Hutton92) due to the nature
of R's data structures. Since R does not support the concept of a list of
tuples, we must revert to using a list rather than a vector, since all values
in an R vector must be the same datatype.
Usage
many(p)
Arguments
p |
is the parser to match 0 or more times. |
See Also
Examples
Digit <- function(...) {satisfy(function(x) {return(!!length(grep("[0-9]", x)))})}
many(Digit()) ("123abc")
many(Digit()) ("abc")
maybe matches 0 or 1 of pattern p. In EBNF notation, this
corresponds to a question mark ('?').
Description
maybe matches 0 or 1 of pattern p. In EBNF notation, this
corresponds to a question mark ('?').
Usage
maybe(p)
Arguments
p |
is the parser to be matched 0 or 1 times. |
See Also
Examples
maybe(Digit())("123abc")
maybe(Digit())("abc123")
nat is a parser which matches one or more numeric characters.
Description
nat is a parser which matches one or more numeric characters.
Usage
nat()
See Also
Digit, Lower, Upper,
Alpha, AlphaNum, SpaceCheck,
String, ident,
space, token, identifier,
natural, symbol
Examples
nat() ("123 + 456")
natural creates a token parser for natural numbers
Description
natural creates a token parser for natural numbers
Usage
natural(...)
Arguments
... |
additional arguments for the parser |
See Also
Digit, Lower, Upper,
Alpha, AlphaNum, SpaceCheck,
String, ident, nat,
space, token, identifier,
symbol
satisfy is a function which allows us to make parsers that recognise single symbols.
Description
satisfy is a function which allows us to make parsers that recognise single symbols.
Usage
satisfy(p)
Arguments
p |
is the predicate to determine if the arbitrary symbol is a member. |
some matches 1 or more of pattern p. in BNF notation, repetition occurs often enough to merit its own abbreviation. When zero or
more repetitions of a phrase p are admissible, we simply write
p+. The some combinator corresponds directly to this operator,
and is defined in much the same way.
Description
some matches 1 or more of pattern p. in BNF notation, repetition occurs often enough to merit its own abbreviation. When zero or
more repetitions of a phrase p are admissible, we simply write
p+. The some combinator corresponds directly to this operator,
and is defined in much the same way.
Usage
some(p)
Arguments
p |
is the parser to match 1 or more times. |
See Also
Examples
Digit <- function(...) {satisfy(function(x) {return(!!length(grep("[0-9]", x)))})}
some(Digit()) ("123abc")
space matches zero or more space characters.
Description
space matches zero or more space characters.
Usage
space()
See Also
Digit, Lower, Upper,
Alpha, AlphaNum, SpaceCheck,
String, ident, nat,
token, identifier,
natural, symbol
Examples
space() (" abc")
succeed is based on the empty string symbol in the BNF notation The
succeed parser always succeeds, without actually consuming any input
string. Since the outcome of succeed does not depend on its input, its result
value must be pre-detemined, so it is included as an extra parameter.
Description
succeed is based on the empty string symbol in the BNF notation The
succeed parser always succeeds, without actually consuming any input
string. Since the outcome of succeed does not depend on its input, its result
value must be pre-detemined, so it is included as an extra parameter.
Usage
succeed(string)
Arguments
string |
the result value of succeed parser |
Examples
succeed("1") ("abc")
symbol creates a token for a symbol
Description
symbol creates a token for a symbol
Usage
symbol(xs)
Arguments
xs |
takes in a string to create a token |
See Also
Digit, Lower, Upper,
Alpha, AlphaNum, SpaceCheck,
String, ident, nat,
space, token, identifier,
natural
Examples
symbol("[") (" [123]")
then combinator corresponds to sequencing in BNF. The parser
(then(p1, p2)) recognises anything that p1 and p2 would
if placed in succession.
Description
%then% is the infix operator for the then combinator, and it is the
preferred way to use the then operator.
Usage
then(p1, p2)
Arguments
p1 |
the first parser |
p2 |
the second parser |
Value
recognises anything that p1 and p2 would if placed in
succession.
See Also
Examples
(item() %then% succeed("123")) ("abc")
thentree keeps the full tree representation of the results of parsing.
Otherwise, it is identical to then.
Description
thentree keeps the full tree representation of the results of parsing.
Otherwise, it is identical to then.
Usage
thentree(p1, p2)
Arguments
p1 |
the first parser |
p2 |
the second parser |
Value
recognises anything that p1 and p2 would if placed in
succession.
See Also
Examples
(item() %thentree% succeed("123")) ("abc")
token is a new primitive that ignores any space before and after
applying a parser to a token.
Description
token is a new primitive that ignores any space before and after
applying a parser to a token.
Usage
token(p)
Arguments
p |
is the parser to have spaces stripped. |
See Also
Digit, Lower, Upper,
Alpha, AlphaNum, SpaceCheck,
String, ident, nat,
space, identifier,
natural, symbol
Examples
token(ident()) (" variable1 ")
using combinator allows us to manipulate results from a parser, for
example building a parse tree. The parser (p %using% f) has the same
behaviour as the parser p, except that the function f is
applied to each of its result values.
Description
%using% is the infix operator for using, and it is the
preferred way to use the using operator.
Usage
using(p, f)
Arguments
p |
is the parser to be applied |
f |
is the function to be applied to each result of |
Value
The parser (p %using% f) has the same behaviour as the
parser p, except that the function f is applied to each of
its result values.
Examples
(item() %using% as.numeric) ("1abc")