I discovered a limitation of FileMaker Pro's Perform AppleScript script step that I believe should either be remedied or documented as a limitation in FileMaker Pro's Script Steps Reference.
Below are some words that macOS Script Editor allows as names for AppleScript variables and functions, but FileMaker's Perform AppleScript script step does not allow.
I discovered that all of these words appear in FileMaker Pro's Scripting Definition file, located inside the FileMaker app at Contents/Resources/fmpro.sdef. Rather than allowing me to create AppleScript variables named "guest" or "single", as Script Editor does, FileMaker Pro is treating those words as the enumerators with those names that are defined in the Scripting Definition file.
Can this limitation be remedied? If not, can FileMaker Pro's documentation be updated to show the complete list of reserved words that FileMaker Pro will not allow as names for AppleScript variables, even though Script Editor does?