Identifiers and static name abstraction

TL;DR: This paper discusses a scheme recently incorporated into Modcap that both mitigates this deficiency and allow s more readable identifiers.

Abstract: Identifiers are used in programming systems to name assorted quantities such as variables, functions , fields, exceptions, files, and labels . The form of an identifier varies from programming language to programming language and sometimes from use to use within a single language or system . However, there i s increasingly a common intersection among modern languages with respect to identifier syntax . For instance , most languages now require an identifier to begin with a letter, allow mixed letters and digits after that, an d utilize an underscore to emulate a hyphen or space in long identifiers . While satisfactory, there are times when more readable programs would be possible if other characters such as operator symbols, punctuation symbol s or blank spaces were permitted within identifiers . More important than the form of identifiers is their concordant use. In the Modcap programmin g language [We185/87/89], identifiers (apart from twelve reserved words) are used only to name \"variables\" o f the various preand user-defined set-theoretic types . The quotation marks are used here because a variable with a very small (e .g., singleton) type cannot actually vary ; it is effectively a named constant . This consistency has the significant benefit that the user has only one set of name-scope rules to learn. The mos t annoying negative aspect has been the lack of a simple mnemonic field referencing facility for structures . This paper discusses a scheme recently incorporated into Modcap that both mitigates this deficiency and allow s more readable identifiers . The idea is to allow static strings to be used as identifiers . This was feasible because of the existence of advanced features such as first-class multivalued functions and automatic stati c instantiation (in-line code substitution) within the language . It is a natural extension to Modcap's existin g naming facilities that essentially and effectively subsumes the field-referencing notation of Pascal and th e object-oriented notation of Smalltalk . Once discovered, it was fully implemented in less than two days .