From 7b85fd99610d284d75fa37f86e8a427ae998892f Mon Sep 17 00:00:00 2001
From: Nyall Dawson <nyall.dawson@gmail.com>
Date: Wed, 5 Sep 2018 17:49:06 +1000
Subject: [PATCH] Allow setting expression format help string for
 QgsExpressionLineEdit

---
 .../qgsexpressionbuilderdialog.sip.in         | 15 ++++++-------
 .../qgsexpressionlineedit.sip.in              | 21 +++++++++++++++++++
 src/gui/qgsexpressionbuilderdialog.h          | 12 +++++------
 src/gui/qgsexpressionlineedit.cpp             | 11 ++++++++++
 src/gui/qgsexpressionlineedit.h               | 18 ++++++++++++++++
 5 files changed, 62 insertions(+), 15 deletions(-)

diff --git a/python/gui/auto_generated/qgsexpressionbuilderdialog.sip.in b/python/gui/auto_generated/qgsexpressionbuilderdialog.sip.in
index 664e7ed426d..13d62aca0ef 100644
--- a/python/gui/auto_generated/qgsexpressionbuilderdialog.sip.in
+++ b/python/gui/auto_generated/qgsexpressionbuilderdialog.sip.in
@@ -37,22 +37,19 @@ The builder widget that is used by the dialog
 
     QString expectedOutputFormat();
 %Docstring
-The set expected format string. This is pure text format and no expression validation
+Returns the expected format string, which is shown in the dialog.
+This is purely a text format and no expression validation
 is done against it.
 
-:return: The expected value format.
+.. seealso:: :py:func:`setExpectedOutputFormat`
 %End
 
     void setExpectedOutputFormat( const QString &expected );
 %Docstring
-The set expected format string. This is pure text format and no expression validation
-is done against it.
+Set the ``expected`` format string, which is shown in the dialog.
+This is purely a text format and no expression validation is done against it.
 
-:param expected: The expected value format for the expression.
-
-.. note::
-
-   Only a UI hint and not used for expression validation.
+.. seealso:: :py:func:`expectedOutputFormat`
 %End
 
     QgsExpressionContext expressionContext() const;
diff --git a/python/gui/auto_generated/qgsexpressionlineedit.sip.in b/python/gui/auto_generated/qgsexpressionlineedit.sip.in
index 1f5e8e7a936..86b6ae2feb3 100644
--- a/python/gui/auto_generated/qgsexpressionlineedit.sip.in
+++ b/python/gui/auto_generated/qgsexpressionlineedit.sip.in
@@ -63,6 +63,27 @@ Sets whether the widget should show a multiline text editor.
                   to show single line editor (the default).
 %End
 
+    QString expectedOutputFormat() const;
+%Docstring
+Returns the expected format string, which is shown in the expression builder dialog for the widget.
+This is purely a text format and no expression validation
+is done against it.
+
+.. seealso:: :py:func:`setExpectedOutputFormat`
+
+.. versionadded:: 3.4
+%End
+
+    void setExpectedOutputFormat( const QString &expected );
+%Docstring
+Set the ``expected`` format string, which is shown in the expression builder dialog for the widget.
+This is purely a text format and no expression validation is done against it.
+
+.. seealso:: :py:func:`expectedOutputFormat`
+
+.. versionadded:: 3.4
+%End
+
     void setGeomCalculator( const QgsDistanceArea &distanceArea );
 %Docstring
 Set the geometry calculator used in the expression dialog.
diff --git a/src/gui/qgsexpressionbuilderdialog.h b/src/gui/qgsexpressionbuilderdialog.h
index 3e55425775f..6eb5f3f47b2 100644
--- a/src/gui/qgsexpressionbuilderdialog.h
+++ b/src/gui/qgsexpressionbuilderdialog.h
@@ -48,17 +48,17 @@ class GUI_EXPORT QgsExpressionBuilderDialog : public QDialog, private Ui::QgsExp
     QString expressionText();
 
     /**
-     * The set expected format string. This is pure text format and no expression validation
+     * Returns the expected format string, which is shown in the dialog.
+     * This is purely a text format and no expression validation
      * is done against it.
-     * \returns The expected value format.
+     * \see setExpectedOutputFormat()
      */
     QString expectedOutputFormat();
 
     /**
-     * The set expected format string. This is pure text format and no expression validation
-     * is done against it.
-     * \param expected The expected value format for the expression.
-     * \note Only a UI hint and not used for expression validation.
+     * Set the \a expected format string, which is shown in the dialog.
+     * This is purely a text format and no expression validation is done against it.
+     * \see expectedOutputFormat()
      */
     void setExpectedOutputFormat( const QString &expected );
 
diff --git a/src/gui/qgsexpressionlineedit.cpp b/src/gui/qgsexpressionlineedit.cpp
index 1a747ed85f6..a92c75cf00a 100644
--- a/src/gui/qgsexpressionlineedit.cpp
+++ b/src/gui/qgsexpressionlineedit.cpp
@@ -103,6 +103,16 @@ void QgsExpressionLineEdit::setMultiLine( bool multiLine )
   }
 }
 
+QString QgsExpressionLineEdit::expectedOutputFormat() const
+{
+  return mExpectedOutputFormat;
+}
+
+void QgsExpressionLineEdit::setExpectedOutputFormat( const QString &expected )
+{
+  mExpectedOutputFormat = expected;
+}
+
 void QgsExpressionLineEdit::setGeomCalculator( const QgsDistanceArea &da )
 {
   mDa.reset( new QgsDistanceArea( da ) );
@@ -151,6 +161,7 @@ void QgsExpressionLineEdit::editExpression()
   QgsExpressionContext context = mExpressionContextGenerator ? mExpressionContextGenerator->createExpressionContext() : mExpressionContext;
 
   QgsExpressionBuilderDialog dlg( mLayer, currentExpression, this, QStringLiteral( "generic" ), context );
+  dlg.setExpectedOutputFormat( mExpectedOutputFormat );
   if ( mDa )
   {
     dlg.setGeomCalculator( *mDa );
diff --git a/src/gui/qgsexpressionlineedit.h b/src/gui/qgsexpressionlineedit.h
index 35296dd8e94..ec438219bc5 100644
--- a/src/gui/qgsexpressionlineedit.h
+++ b/src/gui/qgsexpressionlineedit.h
@@ -78,6 +78,23 @@ class GUI_EXPORT QgsExpressionLineEdit : public QWidget
      */
     void setMultiLine( bool multiLine );
 
+    /**
+     * Returns the expected format string, which is shown in the expression builder dialog for the widget.
+     * This is purely a text format and no expression validation
+     * is done against it.
+     * \see setExpectedOutputFormat()
+     * \since QGIS 3.4
+     */
+    QString expectedOutputFormat() const;
+
+    /**
+     * Set the \a expected format string, which is shown in the expression builder dialog for the widget.
+     * This is purely a text format and no expression validation is done against it.
+     * \see expectedOutputFormat()
+     * \since QGIS 3.4
+     */
+    void setExpectedOutputFormat( const QString &expected );
+
     /**
      * Set the geometry calculator used in the expression dialog.
      * \param distanceArea calculator
@@ -160,6 +177,7 @@ class GUI_EXPORT QgsExpressionLineEdit : public QWidget
     QgsExpressionContext mExpressionContext;
     const QgsExpressionContextGenerator *mExpressionContextGenerator = nullptr;
     QgsVectorLayer *mLayer = nullptr;
+    QString mExpectedOutputFormat;
 
     bool isExpressionValid( const QString &expressionStr );