Package net.hydromatic.morel.compile

Class SuchThatShuttle

java.lang.Object

net.hydromatic.morel.ast.Shuttle

net.hydromatic.morel.compile.SuchThatShuttle

class SuchThatShuttle
extends Shuttle

Converts suchThat to in wherever possible.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
(package private) static class	SuchThatShuttle.FromState	Workspace for converting a particular Core.From from "suchthat" to "in" form.
private static class	SuchThatShuttle.PatMap	Maps patterns from their name in the "from" to their name after a sequence of renames.
private static class	SuchThatShuttle.RewriteFailedException	Signals that we could not rewrite.

Field Summary

Fields

Modifier and Type	Field	Description
(package private) final Environment	env
(package private) final Deque<SuchThatShuttle.FromState>	fromStates

Fields inherited from class net.hydromatic.morel.ast.Shuttle

typeSystem

Constructor Summary

Constructors

Constructor	Description
SuchThatShuttle(TypeSystem typeSystem, Environment env)

Method Summary

Modifier and Type	Method	Description
private static void	addConjunctions(com.google.common.collect.ImmutableList.Builder<Core.Exp> b, Core.Exp e)
(package private) static List<Core.Exp>	conjunctions(Core.Exp e)	Returns an expression as a list of conjunctions.
(package private) static boolean	containsSuchThat(Core.Decl decl)
private Core.Exp	rewrite(UnaryOperator<Core.NamedPat> mapper, SortedMap<Core.NamedPat,Core.Exp> boundPats, Map<Core.IdPat,Core.Exp> scans, List<Core.Exp> filters, List<Core.Exp> exps)	Rewrites a "from vars suchthat condition" expression to a "from vars in list" expression; returns null if no rewrite is possible.
private Core.Exp	rewrite0(SortedMap<Core.NamedPat,Core.Exp> boundPats, Core.Pat pat, Core.Exp exp)
private @Nullable Core.Exp	rewriteElem(TypeSystem typeSystem, UnaryOperator<Core.NamedPat> mapper, SortedMap<Core.NamedPat,Core.Exp> boundPats, Map<Core.IdPat,Core.Exp> scans, List<Core.Exp> filters, Core.Exp a0, Core.Exp a1, List<Core.Exp> exps2)
protected Core.Exp	visit(Core.From from)
protected Core.Scan	visit(Core.Scan scan)

Methods inherited from class net.hydromatic.morel.ast.Shuttle

visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visitList, visitMap, visitSortedMap

Methods inherited from class java.lang.Object

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

Field Details

fromStates

final Deque<SuchThatShuttle.FromState> fromStates

env

final Environment env

Constructor Details

SuchThatShuttle

SuchThatShuttle(TypeSystem typeSystem,
 Environment env)

Method Details

containsSuchThat

static boolean containsSuchThat(Core.Decl decl)

visit

protected Core.Exp visit(Core.From from)

Overrides:

visit in class Shuttle

visit

protected Core.Scan visit(Core.Scan scan)

Overrides:

visit in class Shuttle

rewrite0

private Core.Exp rewrite0(SortedMap<Core.NamedPat,Core.Exp> boundPats,
 Core.Pat pat,
 Core.Exp exp)

rewrite

private Core.Exp rewrite(UnaryOperator<Core.NamedPat> mapper,
 SortedMap<Core.NamedPat,Core.Exp> boundPats,
 Map<Core.IdPat,Core.Exp> scans,
 List<Core.Exp> filters,
 List<Core.Exp> exps)

Rewrites a "from vars suchthat condition" expression to a "from vars in list" expression; returns null if no rewrite is possible.

The "filters" argument contains a list of conditions to be applied after generating rows. For example, "from x suchthat x % 2 = 1 and x elem list" becomes "from x in list where x % 2 = 1" with the filter "x % 2 = 1".

The "scans" argument contains scans to be added. For example, "from x suchthat x elem list" adds the scan "(x, list)".

The "boundPats" argument contains expressions that are bound to variables. For example, "from (x, y) suchthat (x, y) elem list" will add the scan "(e, list)" and boundPats [(x, #1 e), (y, #2 e)].

Parameters:

mapper - Renames variables

boundPats - Variables that have been bound to a list

scans - Scans (joins) to be appended to the resulting "from"

filters - Filters to be appended as "where" in the resulting "from"

exps - The condition, decomposed into conjunctions

Returns:

Rewritten expression

rewriteElem

private @Nullable Core.Exp rewriteElem(TypeSystem typeSystem,
 UnaryOperator<Core.NamedPat> mapper,
 SortedMap<Core.NamedPat,Core.Exp> boundPats,
 Map<Core.IdPat,Core.Exp> scans,
 List<Core.Exp> filters,
 Core.Exp a0,
 Core.Exp a1,
 List<Core.Exp> exps2)

conjunctions

static List<Core.Exp> conjunctions(Core.Exp e)

Returns an expression as a list of conjunctions.

For example conjunctions(a andalso b) returns [a, b] (two elements); conjunctions(a andalso b andalso c) returns [a, b, c] (three elements); conjunctions(a orelse b) returns [a orelse b] (one element); conjunctions(true) returns [] (no elements); conjunctions(false) returns [false] (one element).

addConjunctions

private static void addConjunctions(com.google.common.collect.ImmutableList.Builder<Core.Exp> b,
 Core.Exp e)