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| ///////////////////////////////////////////////////////////////////////////
// //
// Copyright (c) 2015 by Charta Software B.V. //
// All rights reserved //
// //
// Version: 1.7.0.83525 //
// Web site: https://pascal.chartasoftware.com/ //
// //
// This code and information are provided "as is" without warranty of //
// any kind. Dissemination of this information or reproduction of //
// this material is strictly forbidden unless prior written permission //
// is obtained from Charta Software B.V.. //
// //
///////////////////////////////////////////////////////////////////////////
unit Code.Expression;
interface
uses
Boolean,
Collection.List,
Integer._32,
Object_.ReferenceCounted,
Text;
type
TExpression = class(TReferenceCountedObject)
public
class function ParseExpression(ColumnIndex: TInteger32; Value: TText): TExpression;
class function OrAll(Expressions: TList<TExpression>; FreeExpressions: TBoolean = True): TExpression;
class function AndAll(Expressions: TList<TExpression>; FreeExpressions: TBoolean = True): TExpression;
end;
TLiteralText = class(TExpression)
private
FValue: TText;
public
constructor Create(const Value: TText); reintroduce; virtual;
property Value: TText read FValue;
end;
TColumnReference = class(TExpression)
private
FColumnIndex: TInteger32;
public
constructor Create(ColumnIndex: TInteger32); reintroduce; virtual;
property ColumnIndex: TInteger32 read FColumnIndex;
end;
TUnaryExpression = class(TExpression)
private
FOperand: TExpression;
public
constructor Create(Operand: TExpression); reintroduce; virtual;
destructor Destroy(); override;
property Operand: TExpression read FOperand;
end;
TBinaryExpression = class(TExpression)
private
FLeft: TExpression;
FRight: TExpression;
public
constructor Create(Left: TExpression; Right: TExpression); reintroduce; virtual;
destructor Destroy(); override;
property Left: TExpression read FLeft;
property Right: TExpression read FRight;
end;
TLogicalUnaryExpression = class(TUnaryExpression);
TLogicalNot = class(TLogicalUnaryExpression);
TLogicalBinaryExpression = class(TBinaryExpression);
TLogicalAnd = class(TLogicalBinaryExpression);
TLogicalOr = class(TLogicalBinaryExpression);
TComparison = class(TBinaryExpression);
TGreaterThan = class(TComparison);
TGreaterThanOrEqual = class(TComparison);
TLessThan = class(TComparison);
TLessThanOrEqual = class(TComparison);
TLike = class(TExpression)
private
FOperand: TExpression;
FPattern: TText;
public
constructor Create(Operand: TExpression; const Pattern: TText); reintroduce; virtual;
destructor Destroy(); override;
property Operand: TExpression read FOperand;
property Pattern: TText read FPattern;
end;
implementation
uses
Text.Condition.Like;
{ TLike }
constructor TLike.Create(Operand: TExpression; const Pattern: TText);
begin
inherited Create();
FOperand := Operand;
FOperand.AddReference();
FPattern := Pattern;
end;
destructor TLike.Destroy();
begin
Operand.ReleaseReference();
inherited Destroy();
end;
{ TColumnReference }
constructor TColumnReference.Create(ColumnIndex: TInteger32);
begin
inherited Create();
FColumnIndex := ColumnIndex;
end;
{ TBinaryExpression }
constructor TBinaryExpression.Create(Left: TExpression; Right: TExpression);
begin
inherited Create();
FLeft := Left;
FLeft.AddReference();
FRight := Right;
FRight.AddReference();
end;
destructor TBinaryExpression.Destroy();
begin
Left.ReleaseReference();
Right.ReleaseReference();
inherited Destroy();
end;
{ TExpression }
class function TExpression.AndAll(Expressions: TList<TExpression>; FreeExpressions: TBoolean): TExpression;
var
i: TInteger32;
begin
case Expressions.Count of
0: Result := nil;
1:
begin
if FreeExpressions then
begin
Result := Expressions.ExtractFirst();
Result.DiscardReference();
end
else
Result := Expressions[0];
end
else
begin
Result := Expressions[0];
for i := 1 to Expressions.Count - 1 do
Result := TLogicalAnd.Create(Result, Expressions[i]);
end;
end;
if FreeExpressions then
Expressions.Free();
end;
class function TExpression.OrAll(Expressions: TList<TExpression>; FreeExpressions: TBoolean): TExpression;
var
i: TInteger32;
begin
case Expressions.Count of
0: Result := nil;
1:
begin
if FreeExpressions then
begin
Result := Expressions.ExtractFirst();
Result.DiscardReference();
end
else
Result := Expressions[0];
end
else
begin
Result := Expressions[0];
for i := 1 to Expressions.Count - 1 do
Result := TLogicalOr.Create(Result, Expressions[i]);
end;
end;
if FreeExpressions then
Expressions.Free();
end;
class function TExpression.ParseExpression(ColumnIndex: TInteger32; Value: TText): TExpression;
begin
if Value.StartsWith('=') then
Result := TLike.Create(TColumnReference.Create(ColumnIndex), Value.SubtextFrom(1))
else if Value.StartsWith('<>') then
Result := TLogicalNot.Create(TLike.Create(TColumnReference.Create(ColumnIndex), Value.SubtextFrom(2)))
else if Value.StartsWith('<=') then
Result := TLessThanOrEqual.Create(TColumnReference.Create(ColumnIndex), TLiteralText.Create(Value.SubtextFrom(2)))
else if Value.StartsWith('>=') then
Result := TGreaterThanOrEqual.Create(TColumnReference.Create(ColumnIndex), TLiteralText.Create(Value.SubtextFrom(2)))
else if Value.StartsWith('>') then
Result := TGreaterThan.Create(TColumnReference.Create(ColumnIndex), TLiteralText.Create(Value.SubtextFrom(1)))
else if Value.StartsWith('<') then
Result := TLessThan.Create(TColumnReference.Create(ColumnIndex), TLiteralText.Create(Value.SubtextFrom(1)))
else
Result := TLike.Create(TColumnReference.Create(ColumnIndex), TLikeTextCondition.Escape(Value) + '%');
end;
{ TLiteralText }
constructor TLiteralText.Create(const Value: TText);
begin
inherited Create();
FValue := Value;
end;
{ TUnaryExpression }
constructor TUnaryExpression.Create(Operand: TExpression);
begin
inherited Create();
FOperand := Operand;
FOperand.AddReference();
end;
destructor TUnaryExpression.Destroy();
begin
Operand.ReleaseReference();
inherited Destroy();
end;
end.
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