![]() ![]() WARNING the static analysis implemented by trivial/define is unsound in the presence of set!.ĭo not set! in a module that uses trivial/define. 2.1 Built-in Tailorings 2.1.1 Definitions The descriptions below assume familiarity with the Racket reference and describe only the new behavior of the tailored function or form.Ĭlick the name of any tailoring to see its definition in the Racket reference. Note that these tailorings have the same name as their Racket and Typed Racket equivalents to make this library a drop-in replacement for existing code. The following tailorings are all provided by the trivial module. ![]() See Defining new Tailorings for more details. In general, the static properties could be the result of any static analysis.īut this library is limited to properties that other macros can establish through local analysis and propagate via syntax properties. Take the case of a system of linear equations, a 1 x + b 1 y 0 a 3 x + b 4 y 0 a 5 x + b 6 y 0 It is obvious that x y 0 is a solution of such a system of equations. Otherwise, the call to f+ behaves exactly as a call to f would. The subset containing only the identity of a group is a group and it is called trivial. If all goes well, the tailoring will either (1) identify an error or (2) transform the call site into an equivalent- but more efficient or more Typed-Racket-friendly- call. 1.2 Technical DescriptionĪ tailored function f+ is really a macro that examines its call site and attempts to combine knowledge about the behavior of f with static properties of its arguments. ( define ( get-sidekick ( str : String ) ) : StringĪdding ( require trivial ) to the top of the file removes the error. Now try converting it to Typed Racket: #lang typed/racket/base It should compile and run, returning "alfred". Save the following (correct) Racket module: #lang racket/base Trivial Amount means any amount which shall be, from time to time, determined by the Authority which shall not be less than fifty percent of the average statutory minimum wage prescribed by the Cabinet Secretary Trivial Amount means the sum of £260 per year or such higher amount as may be prescribed under section 21 (1) of PSA 93. If you add the line ( require trivial ), the file no longer compiles, but instead gives a helpful error message. ![]() This file will compile no problem ( raco make file.rkt), but will raise a runtime error ( racket file.rkt). Has the same specification and behavior as some library function fīut can catch runtime errors during expansionĪnd may typecheck a little smoother in Typed Racket.įor example, make a new Racket module with a malformed call to format: #lang racket/base Trivial: type- tailored library functions ![]()
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