roadway: vars: refer to files by content rather than by format

[chunhochow]

copied from pull request #18 comment:

e.g. for variables such as excel_df or Excel_File_Path. or for dbf_files etc

when appropriate, refer to the file (also like in the parameter list) as what it is, rather than its format. What is this excel file?

the function argument excel_file can still say excel in some form, if it's important for the reader to know that one should pass in an excel file. but right now I don't know what is this file about. Suggest making it foobar_excel_filepath. (I assume it's a filepath. a file object and a filepath are different things so maybe making it clearer would be better)

but once it's been readed in, we don't have to care that it was read in from an excel file anymore, so we can just say foobar_df.

[chunhochow]

copied from pull request #18 comment:

for dbf_files (LOAD[TOD]_FINAL.dbf), we should name these as loaded_network_files (@sdrewc / @dantischler is this accurate?)
(in general, when possible, we want to say what the file is about, rather than the format (unless if the format is important)

this includes all the parts in the README that refers to these dbf files too

[sdrewc]

copied from pull request #18 comment:

for dbf_files (LOAD[TOD]_FINAL.dbf), we should name these as loaded_network_files (@sdrewc / @dantischler is this accurate?) (in general, when possible, we want to say what the file is about, rather than the format (unless if the format is important)

this includes all the parts in the README that refers to these dbf files too

@chunhochow I agree.

[chunhochow]

Still some remaining variables to clean up after #18