Useful regexs for Debugging

[alwinm]

Brainstorming whether we can use regexes to avoid common typos.

This is an evolving definition (and an evolving idea) but a useful regex would be:

• Compatible with git grep
• A regex that detects a common category of typos
• No false matches
• Documented with an explanation

General regex tips:

-e 
\* # escaped asterisk (for multiplication)
[\s]* # matches arbitrary whitespace 0-unlimited
.? # matches 0-1 arbitrary character

# finds n_cells * id
git grep -e 'n_cells[\s]*\*[\s]*id' 
git grep -e 'id[\s]*\*[\s]*.?.?n_cells' 

# finds + grid_enum
git grep \+[\s]*grid_enum

# finds id * H.n_cells or id * n_cells
git grep -e "id[\s]*\*[\s]*.?.?n_cells" #