The comment about having special notation for different interval types in Mesa caught my eye right away. I constantly make mistakes with "to" and "until" in Sc

The comment about having special notation for different interval types in Mesa caught my eye right away. I constantly make mistakes with "to" and "until" in Scala, where (1 to 9) is the same as (1 until 10). They feel the same, and I've been having a hard time training my brain to treat them differently. I've assumed that using () for exclusive interval bounds and [] for inclusive interval bounds, as in mathematics, would be easier to read. (), [), (], and [] are immediately recognizable visual patterns in mathematical expressions; they're hard to confuse. I often wish I could use them when writing code. However, according to section 3.1.2.1 of the Mesa language manual [1], that was the notation used by Mesa, and according to Dijkstra, it didn't work. It caused errors and confusion. I can guess why -- in mathematics, the braces are made large enough to be visually prominent around the contents. In a line of code all rendered in the same size font, they would be easy to lose and would not hit your subconscious mind the way they do in a mathematical expression. Someday, with better code rendering in editors, maybe we can just use the appropriate braces to indicate whether interval bounds are inclusive or exclusive. [1] http://research.microsoft.com/en-us/um/people/blampson/23a-MesaManual/23a-MesaManual.pdf http://research.microsoft.com/en-us/um/people/blampson/23a-M...