org.dhallj.core

Class Expr

java.lang.Object

org.dhallj.core.Expr

Direct Known Subclasses:

Expr.Parsed

public abstract class Expr
extends java.lang.Object

Represents a Dhall expression.

Note that there are two tools for manipulating expressions: internal visitors, which are a fold over the structure, and external visitors, which correspond to pattern matching.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	Expr.Constants Definitions of Dhall built-ins and other frequently-used expressions.
static class	Expr.ImportMode Modifier specifying how an import should be parsed into a Dhall expression.
static class	Expr.LetBinding<A> Represents the first part of a let-expression.
static class	Expr.Parsed Represents a Dhall expression that's been parsed and has associated source information.
static class	Expr.Util Convenience methods for working with expressions.

Method Summary

Modifier and Type	Method and Description
abstract <A> A	accept(ExternalVisitor<A> visitor) Run the given external visitor on this expression.
<A> A	accept(Visitor<A> visitor) Run the given internal visitor on this expression.
Expr	alphaNormalize() Alpha-normalize this expression.
Expr	decrement(java.lang.String name) Increment a variable name in this expression.
boolean	equals(java.lang.Object obj) Check whether this expression is equivalent to another value.
boolean	equivalent(Expr other) Check whether this expression is equivalent to another.
byte[]	getEncodedBytes() Encode this expression as a CBOR byte array.
byte[]	getHashBytes() Encode this expression as a CBOR byte array and return the SHA-256 hash of the result.
java.lang.String	hash() Encode this expression as a CBOR byte array and return the SHA-256 hash of the result as a string.
int	hashCode() Hashes the CBOR encoding of this expression.
Expr	increment(java.lang.String name) Increment a variable name in this expression.
boolean	isResolved() Check whether all imports in this expression have been resolved.
static Expr	makeAnnotated(Expr base, Expr type)
static Expr	makeApplication(Expr base, Expr arg)
static Expr	makeApplication(Expr base, Expr[] args)
static Expr	makeApplication(Expr base, java.util.List<Expr> args)
static Expr	makeAssert(Expr base)
static Expr	makeBuiltIn(java.lang.String name)
static Expr	makeClasspathImport(java.nio.file.Path path, Expr.ImportMode mode, byte[] hash)
static Expr	makeDoubleLiteral(double value)
static Expr	makeEmptyListLiteral(Expr tpe)
static Expr	makeEnvImport(java.lang.String value, Expr.ImportMode mode, byte[] hash)
static Expr	makeFieldAccess(Expr base, java.lang.String fieldName)
static Expr	makeIdentifier(java.lang.String name)
static Expr	makeIdentifier(java.lang.String name, long index)
static Expr	makeIf(Expr cond, Expr thenValue, Expr elseValue)
static Expr	makeIntegerLiteral(java.math.BigInteger value)
static Expr	makeLambda(java.lang.String param, Expr input, Expr result)
static Expr	makeLet(java.util.List<Expr.LetBinding<Expr>> bindings, Expr body)
static Expr	makeLet(java.lang.String name, Expr value, Expr body)
static Expr	makeLet(java.lang.String name, Expr type, Expr value, Expr body)
static Expr	makeLocalImport(java.nio.file.Path path, Expr.ImportMode mode, byte[] hash)
static Expr	makeMerge(Expr left, Expr right)
static Expr	makeMerge(Expr left, Expr right, Expr type)
static Expr	makeMissingImport(Expr.ImportMode mode, byte[] hash)
static Expr	makeNaturalLiteral(java.math.BigInteger value)
static Expr	makeNonEmptyListLiteral(java.util.Collection<Expr> values)
static Expr	makeNonEmptyListLiteral(Expr[] values)
static Expr	makeNote(Expr base, Source source)
static Expr	makeOperatorApplication(Operator operator, Expr lhs, Expr rhs)
static Expr	makePi(Expr input, Expr result)
static Expr	makePi(java.lang.String param, Expr input, Expr result)
static Expr	makeProjection(Expr base, java.lang.String[] fieldNames)
static Expr	makeProjectionByType(Expr base, Expr tpe)
static Expr	makeRecordLiteral(java.util.Collection<java.util.Map.Entry<java.lang.String,Expr>> fields)
static Expr	makeRecordLiteral(java.util.Map.Entry<java.lang.String,Expr>[] fields)
static Expr	makeRecordLiteral(java.lang.String key, Expr value)
static Expr	makeRecordType(java.util.Collection<java.util.Map.Entry<java.lang.String,Expr>> fields)
static Expr	makeRecordType(java.util.Map.Entry<java.lang.String,Expr>[] fields)
static Expr	makeRemoteImport(java.net.URI url, Expr using, Expr.ImportMode mode, byte[] hash)
static Expr	makeTextLiteral(java.lang.String value)
static Expr	makeTextLiteral(java.lang.String[] parts, java.util.Collection<Expr> interpolated)
static Expr	makeTextLiteral(java.lang.String[] parts, Expr[] interpolated)
static Expr	makeToMap(Expr base)
static Expr	makeToMap(Expr base, Expr type)
static Expr	makeUnionType(java.util.Collection<java.util.Map.Entry<java.lang.String,Expr>> fields)
static Expr	makeUnionType(java.util.Map.Entry<java.lang.String,Expr>[] fields)
static Expr	makeWith(Expr base, java.lang.String[] path, Expr value)
Expr	normalize() Beta-normalize this expression.
boolean	sameStructure(Expr other) Check whether this expression has the same structure as another.
Expr	substitute(java.lang.String name, Expr replacement) Substitute the given expression for the given variable name in this expression.
java.lang.String	toString()

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Method Detail

accept

public abstract <A> A accept(ExternalVisitor<A> visitor)

Run the given external visitor on this expression.

normalize

public final Expr normalize()

Beta-normalize this expression.

This operation "evaluates" the expression.

alphaNormalize

public final Expr alphaNormalize()

Alpha-normalize this expression.

This operation replaces all variable names with De-Bruijn-indexed underscores.

increment

public final Expr increment(java.lang.String name)

Increment a variable name in this expression.

decrement

public final Expr decrement(java.lang.String name)

Increment a variable name in this expression.

substitute

public final Expr substitute(java.lang.String name,
                             Expr replacement)

Substitute the given expression for the given variable name in this expression.

getEncodedBytes

public final byte[] getEncodedBytes()

Encode this expression as a CBOR byte array.

Note that this method does not normalize the expression.

getHashBytes

public final byte[] getHashBytes()

Encode this expression as a CBOR byte array and return the SHA-256 hash of the result.

Note that this method does not normalize the expression.

hash

public final java.lang.String hash()

Encode this expression as a CBOR byte array and return the SHA-256 hash of the result as a string.

Note that this method does not normalize the expression.

isResolved

public final boolean isResolved()

Check whether all imports in this expression have been resolved.

sameStructure

public final boolean sameStructure(Expr other)

Check whether this expression has the same structure as another.

This method is a stricter than equivalent in that it doesn't normalize its arguments.

equivalent

public final boolean equivalent(Expr other)

Check whether this expression is equivalent to another.

Note that this method normalizes both expressions before comparing.

equals

public final boolean equals(java.lang.Object obj)

Check whether this expression is equivalent to another value.

Note that this method normalizes both expressions before comparing. Also note that in future releases this method may compare the hashes of the encoded bytes, but currently it is identical to equivalent (but with an Object argument because Java).

Overrides:

equals in class java.lang.Object

hashCode

public final int hashCode()

Hashes the CBOR encoding of this expression.

Overrides:

hashCode in class java.lang.Object

toString

public final java.lang.String toString()

Overrides:

toString in class java.lang.Object

makeDoubleLiteral

public static final Expr makeDoubleLiteral(double value)

makeNaturalLiteral

public static final Expr makeNaturalLiteral(java.math.BigInteger value)

makeIntegerLiteral

public static final Expr makeIntegerLiteral(java.math.BigInteger value)

makeTextLiteral

public static final Expr makeTextLiteral(java.lang.String[] parts,
                                         Expr[] interpolated)

makeTextLiteral

public static final Expr makeTextLiteral(java.lang.String[] parts,
                                         java.util.Collection<Expr> interpolated)

makeTextLiteral

public static final Expr makeTextLiteral(java.lang.String value)

makeApplication

public static final Expr makeApplication(Expr base,
                                         Expr arg)

makeApplication

public static final Expr makeApplication(Expr base,
                                         Expr[] args)

makeApplication

public static final Expr makeApplication(Expr base,
                                         java.util.List<Expr> args)

makeOperatorApplication

public static final Expr makeOperatorApplication(Operator operator,
                                                 Expr lhs,
                                                 Expr rhs)

makeIf

public static final Expr makeIf(Expr cond,
                                Expr thenValue,
                                Expr elseValue)

makeLambda

public static final Expr makeLambda(java.lang.String param,
                                    Expr input,
                                    Expr result)

makePi

public static final Expr makePi(java.lang.String param,
                                Expr input,
                                Expr result)

makePi

public static final Expr makePi(Expr input,
                                Expr result)

makeAssert

public static final Expr makeAssert(Expr base)

makeFieldAccess

public static final Expr makeFieldAccess(Expr base,
                                         java.lang.String fieldName)

makeProjection

public static final Expr makeProjection(Expr base,
                                        java.lang.String[] fieldNames)

makeProjectionByType

public static final Expr makeProjectionByType(Expr base,
                                              Expr tpe)

makeBuiltIn

public static final Expr makeBuiltIn(java.lang.String name)

makeIdentifier

public static final Expr makeIdentifier(java.lang.String name,
                                        long index)

makeIdentifier

public static final Expr makeIdentifier(java.lang.String name)

makeRecordLiteral

public static final Expr makeRecordLiteral(java.util.Map.Entry<java.lang.String,Expr>[] fields)

makeRecordLiteral

public static final Expr makeRecordLiteral(java.util.Collection<java.util.Map.Entry<java.lang.String,Expr>> fields)

makeRecordLiteral

public static final Expr makeRecordLiteral(java.lang.String key,
                                           Expr value)

makeRecordType

public static final Expr makeRecordType(java.util.Map.Entry<java.lang.String,Expr>[] fields)

makeRecordType

public static final Expr makeRecordType(java.util.Collection<java.util.Map.Entry<java.lang.String,Expr>> fields)

makeUnionType

public static final Expr makeUnionType(java.util.Map.Entry<java.lang.String,Expr>[] fields)

makeUnionType

public static final Expr makeUnionType(java.util.Collection<java.util.Map.Entry<java.lang.String,Expr>> fields)

makeNonEmptyListLiteral

public static final Expr makeNonEmptyListLiteral(Expr[] values)

makeNonEmptyListLiteral

public static final Expr makeNonEmptyListLiteral(java.util.Collection<Expr> values)

makeEmptyListLiteral

public static final Expr makeEmptyListLiteral(Expr tpe)

makeNote

public static final Expr makeNote(Expr base,
                                  Source source)

makeLet

public static final Expr makeLet(java.lang.String name,
                                 Expr type,
                                 Expr value,
                                 Expr body)

makeLet

public static final Expr makeLet(java.util.List<Expr.LetBinding<Expr>> bindings,
                                 Expr body)

makeLet

public static final Expr makeLet(java.lang.String name,
                                 Expr value,
                                 Expr body)

makeAnnotated

public static final Expr makeAnnotated(Expr base,
                                       Expr type)

makeToMap

public static final Expr makeToMap(Expr base,
                                   Expr type)

makeToMap

public static final Expr makeToMap(Expr base)

makeWith

public static final Expr makeWith(Expr base,
                                  java.lang.String[] path,
                                  Expr value)

makeMerge

public static final Expr makeMerge(Expr left,
                                   Expr right,
                                   Expr type)

makeMerge

public static final Expr makeMerge(Expr left,
                                   Expr right)

makeLocalImport

public static final Expr makeLocalImport(java.nio.file.Path path,
                                         Expr.ImportMode mode,
                                         byte[] hash)

makeClasspathImport

public static final Expr makeClasspathImport(java.nio.file.Path path,
                                             Expr.ImportMode mode,
                                             byte[] hash)

makeRemoteImport

public static final Expr makeRemoteImport(java.net.URI url,
                                          Expr using,
                                          Expr.ImportMode mode,
                                          byte[] hash)

makeEnvImport

public static final Expr makeEnvImport(java.lang.String value,
                                       Expr.ImportMode mode,
                                       byte[] hash)

makeMissingImport

public static final Expr makeMissingImport(Expr.ImportMode mode,
                                           byte[] hash)

accept

public final <A> A accept(Visitor<A> visitor)

Run the given internal visitor on this expression.