This is one of many posts to come with advice and tips about things you should do, and things to avoid, when writing Templates. It is intended to help developers who write templates to validate their templates, and to implement some best practices to ensure the templates they deliver work as expected.
The template language is very strict in its syntax, and blank spaces/lines can have a big impact. Spaces where they are not expected are evil. A blank line in the templates will generate a blank line in the generated code, but where that blank line lands in the generated code depends upon where that blank line is within the template code.
Some areas of a template are not meant to generate code, for example #PROMPTs representing the UI. Some templates, like an Extension template, are not supposed to contain any generated code except within #ATs where the code is inserted into an #EMBED.
If a blank line is found in a template, but in a place that is not correct, like between #PROMPTs, or outside a #AT in an Extension template, the code generator will push that line into the generated code, but because the blank line was in an incorrect location there is no explicit place to insert that blank line, and it will add it at the beginning of the block of generated code. To summarize, blank lines in a template are good, except when they are somewhere they are not supposed to be.
Blank lines intended to make the template code easier to read should be always be replaced with #! in column 1 (or just removed). There isn’t a blank line “statement” in the template language, and the reason for that is so that you don’t not mix template language code, with generated output text. Using something like #!———- is much better than a blank line, better in that it is safer and it is more visual.
Some places where a blank line should not be placed:
In any template between a #PROMPT or any other UI code (#SHEET,#TAB,etc.).
In #EXTENSION templates any blank line outside an #AT/#ENDAT block is incorrect.
In a #UTILITY template any blank line outside the scope of an #OPEN or #CREATE is incorrect.
In any template, any blank line used as a separator between #DECLARE statements or as a separator between any other statement is incorrect.
As a golden rule, if the blank line is not intended to be output to the generated code, then the blank line should be replaced by a #! in column 1, or just removed.