Why?

Easier programming

Because of appropriate abstractions, notations and declarative formulations, a DSL program is more concise and readable than its GPL counterpart. Hence, development time is shortened and maintenance is improved. As programming focuses on what to compute as opposed to how to compute, the user does not have to be a skilled programmer. For example, in the case of recompilation, writing a program to explicitly test all file modification times in order to incrementally rebuild a system would clearly be lengthy, tedious and error-prone, as opposed to using a makefile.

Systematic re-use

Most GPL programming environments include the ability to group common operations into libraries. Though some are standard libraries, re-use is left to the programmer. On the other hand, a DSL offers guidelines and built-in functionalities which enforce re-use. Additionally, a DSL captures domain expertise, either implicitly by hiding common program patterns in the DSL implementation, or explicitly by exposing appropriate parameterization to the DSL programmer. Thus, any user necessarily re-uses library components and domain expertise.

Easier verification

Another important advantage of DSLs is that they enable more properties about programs to be checked. In contrast to a GPL, the semantics of a DSL can be restricted to make decidable some properties that are critical to a domain. For example, make reports any cycle in dependencies and thus totally prevents non-termination (assuming the individual actions do not loop).

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