Cadence SKILL

SKILL

Paradigm	functional, OOP
Developer	Cadence Design Systems
First appeared	1990
Stable release	? / ?
Typing discipline	dynamic
Major implementations
Cadence Allegro, Cadence APD, Cadence Concept HDL and Cadence Virtuoso. Major LISP implementation — Cadence UniCAD.
Dialects
SKILL, SKILL++
Influenced by
Scheme, Common Lisp, CLOS

SKILL is a Lisp dialect used as a scripting language and PCell (parameterized cells) description language used in many EDA software suites by Cadence Design Systems. It was originally put forth in an IEEE paper in 1990.

SKILL was originally based on a flavor of Lisp called “Franz Lisp” created at UC Berkeley by the students of Professor Richard J. Fateman. SKILL is not an acronym; it is a name. For trademark reasons Cadence prefers it be capitalized.

Franz Lisp and all other flavors of LISP were eventually superseded by an ANSI standard for Lisp called "Common Lisp." Historically, SKILL was known as IL. SKILL was a library of IL functions. The name was originally an initialism for Silicon Compiler Interface Language (SCIL), pronounced "SKIL", which then morphed into "SKILL", a plain English word that was easier for everyone to remember.

"IL" was just Interface Language. Whilst SKILL was used initially to describe the API rather than the language, the snappier name stuck. The name "IL" remains a common file extension used for SKILL code ".il" designating that the code contained in the file has lisp-2 semantics. Another possible file extension is ".ils" designating that the content has lisp-1 semantics.

Comments are delimited by either the traditional Lisp semicolon

or C-style comments

SKILL programmers have a choice of expression syntaxes. Traditional Lisp syntax such as

can be mixed with C-like syntax such as

White space between the function name and the opening parenthesis, as in

...
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