marijnh/CodeMirror2 — comment on commit 7db287b11adffa2749d84b638c6475bfe943a6ec
File:  line 0
By eustas:

I think, "let" should be a distinct keyword, because if has 3 different syntax forms, and:
"Note: When using the let statement syntax, the parentheses following let are required. Failure to include them will result in a syntax error."