Analysis of information sources in references of the Wikipedia article "سيل (لغة برمجة)" in Arabic language version.
The underscore operator in SAIL source-code assignments printed as a left arrow in the Stanford variant of ASCII, but PDP-10 sites elsewhere just saw it as a plain underscore. However, its use as the assignment operator meant that it could not be used as an extended letter to make compound names more readable, as is now common in many other programming languages. The left arrow in the Stanford variant of ASCII was not the only unusual character.
The underscore operator in SAIL source-code assignments printed as a left arrow in the Stanford variant of ASCII, but PDP-10 sites elsewhere just saw it as a plain underscore. However, its use as the assignment operator meant that it could not be used as an extended letter to make compound names more readable, as is now common in many other programming languages. The left arrow in the Stanford variant of ASCII was not the only unusual character.