SweepFormula: treat non-finite literals (NaN/Inf/-inf) as numeric operands

Packages/MIES/MIES_SweepFormula_Executor.ipf

@@ -695,7 +695,15 @@ static Function/WAVE SFE_FormulaExecutorStringOrVariable(STRUCT SF_ExecutionData
 	return SFH_GetOutputForExecutorSingle(outT, exd.graph, "ExecutorStringReturn")
 End
 
-static Function/WAVE SFE_ConvertNonFiniteElements(WAVE/T subArray)
+/// @brief Convert a text wave that consists solely of the non-finite literals inf/-inf/NaN into a numeric wave
+///
+/// @return numeric wave with the converted values or a null wave reference if at least one element is not a
+///         non-finite literal
+Function/WAVE SFE_ConvertNonFiniteElements(WAVE/T subArray)
+
+	if(numpnts(subArray) == 0)
+		return $""
+	endif
 
 	Make/FREE/D/N=(DimSize(subArray, ROWS), DimSize(subArray, COLS), DimSize(subArray, LAYERS), DimSize(subArray, CHUNKS)) convert
 	MultiThread convert[][][][] = SFE_ConvertNonFiniteElementsImpl(subArray[p][q][r][s])

Packages/MIES/MIES_SweepFormula_Operations.ipf

@@ -2567,9 +2567,31 @@ static Function/WAVE SFO_OperationXValuesImpl(WAVE/Z input)
 	return output
 End
 
+/// @brief Convert a dataset that consists solely of the non-finite literals inf/-inf/NaN into a numeric wave
+///
+/// This allows primitive operations like `1 - NaN` or `1 - inf` where a non-finite value is entered as bare
+/// literal and is therefore kept as string by the parser. Returns the input unchanged if it is not textual or if
+/// it contains at least one element that is not a non-finite literal.
+static Function/WAVE SFO_ConvertNonFiniteText(WAVE/Z data)
+
+	if(!WaveExists(data) || !IsTextWave(data))
+		return data
+	endif
+
+	WAVE/T dataText  = data
+	WAVE/Z converted = SFE_ConvertNonFiniteElements(dataText)
+	if(!WaveExists(converted))
+		return data
+	endif
+
+	CopyScales dataText, converted
+
+	return converted
+End
+
 static Function/WAVE SFO_IndexOverDataSetsForPrimitiveOperation(STRUCT SF_ExecutionData &exd, string opShort)
 
-	variable dataSetNum0, dataSetNum1
+	variable dataSetNum0, dataSetNum1, i
 	string errMsg, type1, type2, resultType
 
 	SFH_CheckArgumentCount(exd, opShort, 2, maxArgs = 2)
@@ -2578,6 +2600,14 @@ static Function/WAVE SFO_IndexOverDataSetsForPrimitiveOperation(STRUCT SF_Execut
 	WAVE/WAVE arg1 = SF_ResolveDatasetFromJSON(exd, 1)
 	dataSetNum0 = DimSize(arg0, ROWS)
 	dataSetNum1 = DimSize(arg1, ROWS)
+
+	// treat the non-finite literals inf/-inf/NaN as numeric operands, see #1863
+	for(i = 0; i < dataSetNum0; i += 1)
+		arg0[i] = SFO_ConvertNonFiniteText(arg0[i])
+	endfor
+	for(i = 0; i < dataSetNum1; i += 1)
+		arg1[i] = SFO_ConvertNonFiniteText(arg1[i])
+	endfor
 	if(dataSetNum0 == 0 && dataSetNum1 == 0)
 		WAVE/WAVE output = SFH_CreateSFRefWave(exd.graph, opShort, 0)
 		return output

Packages/doc/SweepFormula.rst

@@ -198,6 +198,9 @@ The array evaluation supports numeric and text data. The interpretation of the J
 text data is preferred. This means that `["NaN"]` returns a one element text wave `{"NaN"}`,
 whereas `[1, "NaN"]` returns a two element numeric wave `{1, NaN}`. If one element can not be
 parsed as string then it is assumed that the array contains numeric data.
+The non-finite literals `inf`, `-inf` and `NaN` are also accepted as operands of the primitive
+operations `+`, `-`, `*` and `/`, so that e.g. `1 - NaN` and `1 - inf` are valid and evaluate them
+as numeric values.
 The JSON null element is only allowed for the topmost array as the parser inserts it for
 operation with no argument like e.g. `select()`. For sub arrays null elements `[null]`
 are invalid and result in an error.

Packages/tests/Basic/UTF_SweepFormula.ipf

@@ -110,20 +110,39 @@ static Function TestNonFiniteValues()
 	TestOperationMinMaxHelper(win, "\"NaN\"", "NaN", NaN)
 End
 
-// Fails with Abort
-// UTF_TD_GENERATOR DataGenerators#NonFiniteValues
-//static Function TestNonFiniteValuesPrimitiveOperations([variable var])
-//
-//	string win, device, str
-//
-//	[win, device] = CreateEmptyUnlockedDataBrowserWindow()
-//
-//	str = "\"" + num2str(var) + "\""
-//	TestOperationMinMaxHelper(win, "{\"+\":[1," + str + "]}", "1+" + str, 1 + var)
-//	TestOperationMinMaxHelper(win, "{\"*\":[1," + str + "]}", "1*" + str, 1 * var)
-//	TestOperationMinMaxHelper(win, "{\"-\":[1," + str + "]}", "1-" + str, 1 - var)
-//	TestOperationMinMaxHelper(win, "{\"/\":[1," + str + "]}", "1/" + str, 1 / var)
-//End
+static Function TestNonFiniteValuesPrimitiveOperations()
+
+	string win
+
+	win = GetDataBrowserWithData()
+
+	// non-finite values entered as bare literals are kept as string by the parser (see #1863)
+	CheckEqualFormulas("{\"+\":[1,\"NaN\"]}", "1+NaN")
+	CheckEqualFormulas("{\"-\":[1,\"NaN\"]}", "1-NaN")
+	CheckEqualFormulas("{\"*\":[1,\"NaN\"]}", "1*NaN")
+	CheckEqualFormulas("{\"/\":[1,\"NaN\"]}", "1/NaN")
+
+	// and are converted to numeric values when used in primitive operations
+	WAVE data = SFE_ExecuteFormula("1+NaN", win, singleResult = 1, useVariables = 0)
+	CHECK_EQUAL_WAVES(data, {NaN}, mode = WAVE_DATA)
+	WAVE data = SFE_ExecuteFormula("1-NaN", win, singleResult = 1, useVariables = 0)
+	CHECK_EQUAL_WAVES(data, {NaN}, mode = WAVE_DATA)
+	WAVE data = SFE_ExecuteFormula("1*NaN", win, singleResult = 1, useVariables = 0)
+	CHECK_EQUAL_WAVES(data, {NaN}, mode = WAVE_DATA)
+	WAVE data = SFE_ExecuteFormula("1/NaN", win, singleResult = 1, useVariables = 0)
+	CHECK_EQUAL_WAVES(data, {NaN}, mode = WAVE_DATA)
+
+	WAVE data = SFE_ExecuteFormula("1-inf", win, singleResult = 1, useVariables = 0)
+	CHECK_EQUAL_WAVES(data, {-Inf}, mode = WAVE_DATA)
+	WAVE data = SFE_ExecuteFormula("1+inf", win, singleResult = 1, useVariables = 0)
+	CHECK_EQUAL_WAVES(data, {+Inf}, mode = WAVE_DATA)
+	WAVE data = SFE_ExecuteFormula("1--inf", win, singleResult = 1, useVariables = 0)
+	CHECK_EQUAL_WAVES(data, {+Inf}, mode = WAVE_DATA)
+	WAVE data = SFE_ExecuteFormula("1*inf", win, singleResult = 1, useVariables = 0)
+	CHECK_EQUAL_WAVES(data, {+Inf}, mode = WAVE_DATA)
+	WAVE data = SFE_ExecuteFormula("1/inf", win, singleResult = 1, useVariables = 0)
+	CHECK_EQUAL_WAVES(data, {0}, mode = WAVE_DATA)
+End
 
 static Function TestScientificNotation()