14 parsing single character variables fails

[ClaasRostock]

Single character references were not correctly extracted from block_content.
Reason was the regex used to find them.

• replaced all occurences of \$\w[\w\[\]]+ with \$\w[\w\[\]]* (i.e. using * instead of + )
• added unit tests to check that single character references get correctly identified, extracted and resolved.

[frl000]

I tried to adapt for single character keyword vectors. For single component it worked, so I think the issue is fixed.
I have no clue why and when this "$\w[\w[]]+" was introduced, but probably "someone" had no single char. keywords in mind. And it is surely a bad manner.
I marked an issue that I found with mixed string lists in test_dictReader.py:594, any idea what I missed there?

[frl000]

oops. No python string concatenation. This is simply substitution.

[ClaasRostock]

oops. No python string concatenation. This is simply substitution.

Hi Frank, @frl000

great test that you added with the reference lists, I like it :-)
The problem was the format of how you declared the "concatenated" string expression in test_single_characters_vars_dict.
a) You used single quotes around the expression. However, expressions by definition must be enclosed in double quotes, otherwise they will not be identified as expression (but as string literal instead).
b) the + operator fails to concatenate the strings because, once the individual strings in the expression are resolved, they are put back into the expression without quotes. evaluation of "Alice + and + Bob" then has no effect. The quoting in the expression after resolving the referenced strings would need to look like "'Alice' + 'and' + 'Bob'" in order to have evalution turn that into "AliceandBob". However, I have no idea currently how we could accomplish that behaviour without unwanted side effects. Nested quoting in the dict I quickly tried, but that does not yield the intended result. I resolved this particluar problem then by changing "$m[0] + $m[1] + $m[2] + $m[3] + $m[4] + $m[5]" to simply "$m[0]$m[1]$m[2]$m[3]$m[4]$m[5]". With that, result is what you probably intended, and the test passes.