using curly braces "{" or "}" in a comment in an iRule

The sensitivity to whitespace is inherent in the Tcl language itself, and is not restricted to its use in BIG-IP iRules. When we teach iRules in our customer-facing training, one of the first things we point out is how impactful whitespace is on interpretation. The presence of whitespace delineates the potential start of something new, like a new command or a new positional parameter or a new operand. In other programming languages, command terminator characters (like ";") are required to delineate the end of a command. But not in Tcl. Every piece of whitespace has potential relevance, which is why special grouping characters, such as brackets and curly braces (to name but two) are also important. They are used to indicate the start or end of a series of grouped strings that contain whitespace. But this syntax is part of the language and something you simply must get used to when writing Tcl "programs."