Coordinate format (REAL type) not correct

[hemanti0503]

Background

https://www.steptools.com/stds/step/IS_final_p21e3.html#clause-6-4-2 defines the REAL data type as follows:

The encoding shall consist of a decimal mantissa optionally followed by a decimal exponent. The decimal mantissa consists of an optional plus sign "+" or minus sign "-", followed by a sequence of one or more digits, followed by a full stop ".", followed by a sequence of zero or more digits. A decimal exponent consists of the latin capital letter E optionally followed by a plus sign "+" or minus sign "-", followed by one or more digits.

In particular, this is given as an invalid example:

Invalid real expressions	Problem
1E05	Decimal point required in mantissa

Issue/Example

However, this invalid example is exactly the way that steputils formats coordinates. For example:

#1177=CARTESIAN_POINT('Vertex',(1.84999999998,5.70100354408,7.80860104192)) ; becomes #1177=CARTESIAN_POINT('Vertex',(-2E-11,5.70100354408,7.80860104192)); when executing the following code:

for ref, currentEntity in stepfile.data[0].instances.copy().items():
	if isinstance(currentEntity, p21.SimpleEntityInstance) == True:
		if currentEntity.entity.name == "CARTESIAN_POINT":
			newPosX = Decimal('-1.85')
			newCartesianParameters = [currentEntity.entity.params[0], [newPosX, currentEntity.entity.params[1][1], currentEntity.entity.params[1][2]]]
			stepfile.data[0].add(p21.simple_instance(currentEntity.ref, name=currentEntity.entity.name, params=newCartesianParameters))

Possible mitigations and workarounds

• Using simple float for newPosX instead of Decimal does not solve the issue.
• Using string formatting like newPosX = f"{newPosX:f}" does produce valid REAL presentation, but inside a string (which is of course not valid). The output in the example would be as follows: #1177=CARTESIAN_POINT('Vertex',('-0.00000000002',5.70100354408,7.80860104192));
• For now, I will probably post-process the produced file, adding ".0" before every "E" without decimal point before it. However, this doesn't solve the issue, that the library in itself produces invalid STEP files.