Package nz.org.riskscape.rl

Class ExpressionParser

java.lang.Object

nz.org.riskscape.rl.ExpressionParser

public class ExpressionParser
extends Object

Builds a Riskscape Language Expression AST from a string. At the moment, the language is a mostly equivalent version of ECQL that simplifies the language to make it more flexible for use throughout the riskscape engine. Current plans are to extend its use to all uses of Expression and Filter and possibly also taking in type expressions and pipeline expressions.

Field Summary

Fields

Modifier and Type	Field	Description
static final EnumSet<TokenTypes>	IDENTIFIERS	Used with ConditionalParse
static final ExpressionParser	INSTANCE
static final EnumSet<TokenTypes>	KEY_IDENTIFIERS	Used with ConditionalParse
static final EnumSet<TokenTypes>	LEADING_TOKENS	The list of tokens that typically start any expression
static final EnumSet<TokenTypes>	LITERALS	All of the things that can be inside a Constant

Constructor Summary

Constructors

Constructor	Description
ExpressionParser()

Method Summary

Modifier and Type	Method	Description
void	checkForParameters(Expression parsed)
protected Lexer<TokenTypes>	lex(String source)	Lexes source with the TokenTypes.tokens().
Expression	parse(String source)	Parses the given string in to an Expression.
Expression	parseAllowParameters(String source)	A version of parse(String) that allows the expression to contain ParameterTokens.
Expression	parseExpression(Lexer<TokenTypes> lexer)
FunctionCall	parseFunctionExpression(Lexer<TokenTypes> lexer)
ResultOrProblems<Expression>	parseOr(String source)	Convenience method to catch any exceptions from parsing the expression and return them as a ResultOrProblem
PropertyAccess	parsePropertyExpression(Lexer<TokenTypes> lexer, Optional<Expression> receiver)
static Expression	parseString(String source)	Convenience form of new ExpressionParser().parse(source)
ListDeclaration	toList(Expression expr)	Return a version of the given expression as a ListDeclaration.
StructDeclaration	toStruct(Expression expr)	Return a version of the given expression as a struct.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

INSTANCE

public static final ExpressionParser INSTANCE

IDENTIFIERS

public static final EnumSet<TokenTypes> IDENTIFIERS

Used with ConditionalParse

KEY_IDENTIFIERS

public static final EnumSet<TokenTypes> KEY_IDENTIFIERS

Used with ConditionalParse

LITERALS

public static final EnumSet<TokenTypes> LITERALS

All of the things that can be inside a Constant

LEADING_TOKENS

public static final EnumSet<TokenTypes> LEADING_TOKENS

The list of tokens that typically start any expression

NB this is 'derived', which kind of sucks, but it's just for debugging/error messages

Constructor Details

ExpressionParser

public ExpressionParser()

Method Details

parseString

public static Expression parseString(String source)

Convenience form of new ExpressionParser().parse(source)

parse

public Expression parse(String source)

Parses the given string in to an Expression. See parseAllowParameters(String) for a version that accepts ParameterTokens

Returns:

an Expression from the given string

Throws:

ParseException - if source couldn't be parsed or if the expression contains ParameterTokens.

LexerException - if source couldn't be lexed in to tokens

parseOr

public ResultOrProblems<Expression> parseOr(String source)

Convenience method to catch any exceptions from parsing the expression and return them as a ResultOrProblem

parseAllowParameters

public Expression parseAllowParameters(String source)

A version of parse(String) that allows the expression to contain ParameterTokens.

Parameters:

source -

Returns:

Expression

checkForParameters

public void checkForParameters(Expression parsed)

Throws:

ParseException - if the given expression contains $foo style parameters

toStruct

public StructDeclaration toStruct(Expression expr)

Return a version of the given expression as a struct. If it's already a struct declaration it is returned as is, otherwise a simple anonymous struct declaration is put around it.

toList

public ListDeclaration toList(Expression expr)

Return a version of the given expression as a ListDeclaration. If expression is a ListDeclaration it is returned as is, otherwise a ListDeclaration is returned containing expression as the single item.

lex

protected Lexer<TokenTypes> lex(String source)

Lexes source with the TokenTypes.tokens().

Parameters:

source - to lex

parseExpression

public Expression parseExpression(Lexer<TokenTypes> lexer)

parseFunctionExpression

public FunctionCall parseFunctionExpression(Lexer<TokenTypes> lexer)

parsePropertyExpression

public PropertyAccess parsePropertyExpression(Lexer<TokenTypes> lexer,
 Optional<Expression> receiver)