org.dhallj.core

Class Expr.Util

java.lang.Object

org.dhallj.core.Expr.Util

Enclosing class:

Expr

public static final class Expr.Util
extends java.lang.Object

Convenience methods for working with expressions.

Note that many of these operations represent "down-casts", and return null in cases where the expression doesn't have the requested constructor.

Method Summary

Modifier and Type	Method and Description
static Expr	applyAsLambda(Expr expr, Expr arg) If the expression is a lambda, apply it to the given argument.
static java.lang.Boolean	asBoolLiteral(Expr expr) If the expression is a Bool literal, return its value.
static java.lang.String	asBuiltIn(Expr expr) If the expression is a Dhall built-in, return its name.
static java.lang.Double	asDoubleLiteral(Expr expr) If the expression is a Double literal, return its value.
static java.util.Map.Entry<Expr,java.lang.String>	asFieldAccess(Expr expr) If the expression is a field access, return the base and field name.
static java.math.BigInteger	asIntegerLiteral(Expr expr) If the expression is an Integer literal, return its value.
static java.util.List<Expr>	asListLiteral(Expr expr) If the expression is a List literal, return its contents.
static java.math.BigInteger	asNaturalLiteral(Expr expr) If the expression is a Natural literal, return its value.
static java.util.List<java.util.Map.Entry<java.lang.String,Expr>>	asRecordLiteral(Expr expr) If the expression is a record literal, return its fields.
static java.util.List<java.util.Map.Entry<java.lang.String,Expr>>	asRecordType(Expr expr) If the expression is a record type, return its fields.
static java.lang.String	asSimpleTextLiteral(Expr expr) If the expression is a Text literal with no interpolations, return its value.
static java.util.List<java.util.Map.Entry<java.lang.String,Expr>>	asUnionType(Expr expr) If the expression is a union type, return its fields.
static byte[]	decodeHashBytes(java.lang.String input)
static Expr	desugarComplete(Expr lhs, Expr rhs) Desugar the complete operator (::).
static java.lang.String	encodeHashBytes(byte[] hash) Encode an array of bytes as a hex string.
static void	encodeToStream(Expr expr, java.io.OutputStream stream) Write an encoded expression to a stream.
static java.lang.String	escapeText(java.lang.String input, boolean quoted)
static java.util.Map.Entry<Expr,Expr>	getFirstDiff(Expr first, Expr second) Return the first difference between the structure of two expressions as a pair.
static Expr	getListArg(Expr expr) If the expression is an application of List, return the element type.
static Expr	getNoneArg(Expr expr) If the expression is an application of None, return the element type.
static Expr	getOptionalArg(Expr expr) If the expression is an application of Optional, return the element type.
static Expr	getSomeArg(Expr expr) If the expression is an application of Some, return the element type.
static Expr	typeCheck(Expr expr) Type-check the given expression and return the inferred type.

Methods inherited from class java.lang.Object

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

Method Detail

typeCheck

public static final Expr typeCheck(Expr expr)

Type-check the given expression and return the inferred type.

getFirstDiff

public static final java.util.Map.Entry<Expr,Expr> getFirstDiff(Expr first,
                                                                Expr second)

Return the first difference between the structure of two expressions as a pair.

encodeToStream

public static final void encodeToStream(Expr expr,
                                        java.io.OutputStream stream)

Write an encoded expression to a stream.

encodeHashBytes

public static java.lang.String encodeHashBytes(byte[] hash)

Encode an array of bytes as a hex string.

decodeHashBytes

public static final byte[] decodeHashBytes(java.lang.String input)

getListArg

public static Expr getListArg(Expr expr)

If the expression is an application of List, return the element type.

getOptionalArg

public static Expr getOptionalArg(Expr expr)

If the expression is an application of Optional, return the element type.

getSomeArg

public static Expr getSomeArg(Expr expr)

If the expression is an application of Some, return the element type.

getNoneArg

public static Expr getNoneArg(Expr expr)

If the expression is an application of None, return the element type.

asBoolLiteral

public static final java.lang.Boolean asBoolLiteral(Expr expr)

If the expression is a Bool literal, return its value.

asNaturalLiteral

public static final java.math.BigInteger asNaturalLiteral(Expr expr)

If the expression is a Natural literal, return its value.

asIntegerLiteral

public static final java.math.BigInteger asIntegerLiteral(Expr expr)

If the expression is an Integer literal, return its value.

asDoubleLiteral

public static final java.lang.Double asDoubleLiteral(Expr expr)

If the expression is a Double literal, return its value.

asSimpleTextLiteral

public static final java.lang.String asSimpleTextLiteral(Expr expr)

If the expression is a Text literal with no interpolations, return its value.

asBuiltIn

public static final java.lang.String asBuiltIn(Expr expr)

If the expression is a Dhall built-in, return its name.

asListLiteral

public static final java.util.List<Expr> asListLiteral(Expr expr)

If the expression is a List literal, return its contents.

asRecordLiteral

public static final java.util.List<java.util.Map.Entry<java.lang.String,Expr>> asRecordLiteral(Expr expr)

If the expression is a record literal, return its fields.

asRecordType

public static final java.util.List<java.util.Map.Entry<java.lang.String,Expr>> asRecordType(Expr expr)

If the expression is a record type, return its fields.

asUnionType

public static final java.util.List<java.util.Map.Entry<java.lang.String,Expr>> asUnionType(Expr expr)

If the expression is a union type, return its fields.

asFieldAccess

public static final java.util.Map.Entry<Expr,java.lang.String> asFieldAccess(Expr expr)

If the expression is a field access, return the base and field name.

escapeText

public static final java.lang.String escapeText(java.lang.String input,
                                                boolean quoted)

desugarComplete

public static final Expr desugarComplete(Expr lhs,
                                         Expr rhs)

Desugar the complete operator (::).

applyAsLambda

public static final Expr applyAsLambda(Expr expr,
                                       Expr arg)

If the expression is a lambda, apply it to the given argument.

Returns null if the expression is not a lambda.