Interfaces.FZSolutionParser

This module defines a parser for the default format of the output of the two solvers integrated in haskelzinc (G12/FD and choco3). It also provides modular parsers for entities that constitute a solution, such as MiniZinc variable names and values, solutions' separator in case of multiple solutions, etc. These modular parsers can be used in building a parser for a solver's output, the format of which is specified by a MiniZinc output item differs from the default one.

Documentation

data MValue

Representation of returned values.

Constructors

MError String

MInt Int

MFloat Float

MBool Bool

MString String

MArray [MValue]

MSet (Set MValue)

Instances

Show MValue

Methods

showsPrec :: Int -> MValue -> ShowS

show :: MValue -> String

showList :: [MValue] -> ShowS

type Solution = [(String, MValue)]

A Solution consists of a list of pairs. Each pair represents an assignment of a value to a decision variable of the constraint model.

Parsing values

valueM :: Parser MValue

Parses a MiniZinc value. Tries floatM, intM, boolM, setM, arrayM and stringM in this order.

intM :: Parser MValue

Parses a MiniZinc integer value.

boolM :: Parser MValue

Parses a MiniZinc boolean value.

floatM :: Parser MValue

Parses a MiniZinc float value.

stringM :: Parser MValue

Parses a MiniZinc string value.

setM :: Parser MValue -> Parser MValue

Parses a MiniZinc set value.

setRange :: Parser MValue

Parses a MiniZinc set value defined with the use of the MiniZinc range operator (..).

arrayM :: Parser MValue -> Parser MValue

Parses MiniZinc 1-dimensional or multi-dimensional array values.

Solutions

varName :: Parser String

Parses a MiniZinc variable name by trying simpleVarName and quotedVarName.

simpleVarName :: Parser String

Parses a conventional MiniZinc variable identifier. That is, a string of the form [A-Za-z][A-Za-z0-9_]*.

quotedVarName :: Parser String

Parses a quoted MiniZinc identifier.

comment :: Parser String

Parses a comment in the solutions and returns the content.

comments :: Parser String

Parses a sequence of commented lines in the solutions and returns their content.

Default parsers

defaultNameValuePair :: Parser (String, MValue)

Parses a MiniZinc variable name-value pair in a solution with the default output format.

defaultUnsat :: Parser String

Parses the default message for a model with no solutions: =====UNSATISFIABLE=====, surrounded by commented lines before and after.

defaultSolution :: Parser Solution

Parses a single solution with the default output format from the set of returned solutions.

defaultSolutions :: Parser [Solution]

Parses all the returned solutions.

tryDefaultSolutions :: Int -> Parser [Solution]

tryDefaultSolutions n tries to parse the solutions and, if it succeeds, returns the first n. Else, tries defaultUnsat and returns an empty list.

getDefaultSolutions :: Int -> String -> Either ParseError [Solution]

Same as getSolutionFromFile but parses the string argument of the function instead of the contents of a file.

getDefaultSolutionsFromFile :: FilePath -> Int -> IO (Either ParseError [Solution])

Returns either a parse error or a list of solutions of the constraint model, parsed from the file where they are printed. The length of the list is specified by the second argument of the function.

Custom

The following functions can be used when a MiniZinc output item, which alters the default output format of the solver, is present in the model.

nameValuePair

Arguments

:: Parser String

Value-name separator

-> Parser (String, MValue)

Used to parse a MiniZinc variable name-value pair in a solution. nameValuePair s parses succesfully if sequential parsing of varName, s and valueM is succesfull. Returns the MiniZinc name-value pair in a Haskell pair and forgets the result of parser s.

trySolutions :: (Int -> Parser [Solution]) -> Parser String -> Int -> Parser [Solution]

trySolutions f p n applies f n and returns the solutions. If that fails, tries to parse an Unsatisfiable message by applying p and returns an empty list. The custom parser must be parametrized by an integer, for specifying the number of solutions to be returned.

getSolutions :: (Int -> Parser [Solution]) -> Int -> String -> Either ParseError [Solution]

A custom version of getDefaultSolutions. This function accepts a custom parser to parse the solutions. The custom parser must be parametrized by an integer, for specifying the number of solutions to be returned.