#13603 Replace bool/errorText with std::expected in ExpressionParser

evaluate() and expandIfStatementsAndEvaluate() now return std::expected<void, QString>: the error message is always part of the return value rather than an optional out-parameter, making it impossible for callers to silently discard errors.

Update RimGridCalculation and RimSummaryCalculation to use evaluateResult.error() instead of a separate errorText variable.

ThirdParty/expressionparser/ExpressionParser.cpp

@@ -1,17 +1,17 @@
 /////////////////////////////////////////////////////////////////////////////////
 //
 //  Copyright (C) 2017-     Statoil ASA
-// 
+//
 //  ResInsight is free software: you can redistribute it and/or modify
 //  it under the terms of the GNU General Public License as published by
 //  the Free Software Foundation, either version 3 of the License, or
 //  (at your option) any later version.
-// 
+//
 //  ResInsight is distributed in the hope that it will be useful, but WITHOUT ANY
 //  WARRANTY; without even the implied warranty of MERCHANTABILITY or
 //  FITNESS FOR A PARTICULAR PURPOSE.
-// 
-//  See the GNU General Public License at <http://www.gnu.org/licenses/gpl.html> 
+//
+//  See the GNU General Public License at <http://www.gnu.org/licenses/gpl.html>
 //  for more details.
 //
 /////////////////////////////////////////////////////////////////////////////////
@@ -21,59 +21,54 @@
 #include "ExpressionParserImpl.h"
 
 //--------------------------------------------------------------------------------------------------
-/// 
+///
 //--------------------------------------------------------------------------------------------------
 ExpressionParser::ExpressionParser()
 {
-    m_expressionParserImpl = std::unique_ptr<ExpressionParserImpl>(new ExpressionParserImpl);
+    m_expressionParserImpl = std::unique_ptr<ExpressionParserImpl>( new ExpressionParserImpl );
 }
 
 //--------------------------------------------------------------------------------------------------
-/// 
+///
 //--------------------------------------------------------------------------------------------------
 ExpressionParser::~ExpressionParser()
 {
-
 }
 
 //--------------------------------------------------------------------------------------------------
-/// 
+///
 //--------------------------------------------------------------------------------------------------
-std::vector<QString> ExpressionParser::detectReferencedVariables(const QString& expression)
+std::vector<QString> ExpressionParser::detectReferencedVariables( const QString& expression )
 {
-    return ExpressionParserImpl::detectReferencedVariables(expression);
+    return ExpressionParserImpl::detectReferencedVariables( expression );
 }
 
 //--------------------------------------------------------------------------------------------------
-/// 
+///
 //--------------------------------------------------------------------------------------------------
-void ExpressionParser::assignVector(const QString& variableName, std::vector<double>& vector)
+void ExpressionParser::assignVector( const QString& variableName, std::vector<double>& vector )
 {
-    m_expressionParserImpl->assignVector(variableName, vector);
+    m_expressionParserImpl->assignVector( variableName, vector );
 }
 
 //--------------------------------------------------------------------------------------------------
-/// 
+///
 //--------------------------------------------------------------------------------------------------
-bool ExpressionParser::evaluate(const QString& expressionText, QString* errorText)
+std::expected<void, QString> ExpressionParser::evaluate( const QString& expressionText )
 {
-    return m_expressionParserImpl->evaluate(expressionText, errorText);
+    return m_expressionParserImpl->evaluate( expressionText );
 }
 
 //--------------------------------------------------------------------------------------------------
-/// 
+///
 //--------------------------------------------------------------------------------------------------
-bool ExpressionParser::expandIfStatementsAndEvaluate(const QString& expressionText, QString* errorText /*= nullptr*/)
+std::expected<void, QString> ExpressionParser::expandIfStatementsAndEvaluate( const QString& expressionText )
 {
-    if (expressionText.contains("if", Qt::CaseInsensitive))
+    if ( expressionText.contains( "if", Qt::CaseInsensitive ) )
     {
-        QString expandedExpressionText = ExpressionParserImpl::expandIfStatements(expressionText);
-
-        return m_expressionParserImpl->evaluate(expandedExpressionText, errorText);
-    }
-    else
-    {
-        return m_expressionParserImpl->evaluate(expressionText, errorText);
+        QString expanded = ExpressionParserImpl::expandIfStatements( expressionText );
+        return m_expressionParserImpl->evaluate( expanded );
     }
 
+    return m_expressionParserImpl->evaluate( expressionText );
 }

ThirdParty/expressionparser/ExpressionParser.h

@@ -20,13 +20,14 @@
 
 #include <QString>
 
+#include <expected>
 #include <memory>
 #include <vector>
 
 class ExpressionParserImpl;
 
 //==================================================================================================
-/// 
+///
 //==================================================================================================
 class ExpressionParser
 {
@@ -34,11 +35,13 @@ public:
     ExpressionParser();
     ~ExpressionParser();
 
-    static std::vector<QString> detectReferencedVariables(const QString& expression);
+    static std::vector<QString> detectReferencedVariables( const QString& expression );
 
-    void                        assignVector(const QString& variableName, std::vector<double>& vector);
-    bool                        evaluate(const QString& expressionText, QString* errorText = nullptr);
-    bool                        expandIfStatementsAndEvaluate(const QString& expressionText, QString* errorText = nullptr);
+    void assignVector( const QString& variableName, std::vector<double>& vector );
+
+    // Returns an empty expected on success, or an unexpected containing the error message on failure.
+    std::expected<void, QString> evaluate( const QString& expressionText );
+    std::expected<void, QString> expandIfStatementsAndEvaluate( const QString& expressionText );
 
 private:
     std::unique_ptr<ExpressionParserImpl> m_expressionParserImpl;

ThirdParty/expressionparser/ExpressionParserImpl.cpp

@@ -76,32 +76,22 @@ void ExpressionParserImpl::assignVector(const QString& variableName, std::vector
 //--------------------------------------------------------------------------------------------------
 /// 
 //--------------------------------------------------------------------------------------------------
-bool ExpressionParserImpl::evaluate(const QString& expressionText, QString* errorText)
+std::expected<void, QString> ExpressionParserImpl::evaluate( const QString& expressionText )
 {
     expression_t expression;
-
-    expression.register_symbol_table(m_symbol_table);
+    expression.register_symbol_table( m_symbol_table );
 
     parser_t parser;
-    if (!parser.compile(expressionText.toStdString(), expression))
-    {
-        if (errorText)
-        {
-            *errorText = parserErrorText(parser);
-        }
-
-        return false;
-    }
+    if ( !parser.compile( expressionText.toStdString(), expression ) )
+        return std::unexpected( parserErrorText( parser ) );
 
     // Trigger evaluation
     expression.value();
 
-    if (errorText)
-    {
-        *errorText = parserErrorText(parser);
-    }
+    if ( parser.error_count() > 0 )
+        return std::unexpected( parserErrorText( parser ) );
 
-    return (parser.error_count() == 0);
+    return {};
 }
 
 //--------------------------------------------------------------------------------------------------

ThirdParty/expressionparser/ExpressionParserImpl.h

@@ -22,27 +22,29 @@
 
 #include <QString>
 
+#include <expected>
+
 //==================================================================================================
-/// 
+///
 //==================================================================================================
 class ExpressionParserImpl
 {
     typedef exprtk::symbol_table<double> symbol_table_t;
-    typedef exprtk::expression<double>     expression_t;
-    typedef exprtk::parser<double>             parser_t;
+    typedef exprtk::expression<double>   expression_t;
+    typedef exprtk::parser<double>       parser_t;
 
 public:
     ExpressionParserImpl();
 
-    static std::vector<QString> detectReferencedVariables(const QString& expression);
+    static std::vector<QString> detectReferencedVariables( const QString& expression );
 
-    void    assignVector(const QString& variableName, std::vector<double>& vector);
-    bool    evaluate(const QString& expressionText, QString* errorText = nullptr);
-    
-    static QString expandIfStatements(const QString& expressionText);
+    void                         assignVector( const QString& variableName, std::vector<double>& vector );
+    std::expected<void, QString> evaluate( const QString& expressionText );
+
+    static QString expandIfStatements( const QString& expressionText );
 
 private:
-    QString parserErrorText(parser_t& parser);
+    QString parserErrorText( parser_t& parser );
 
 private:
     symbol_table_t m_symbol_table;