Michael Lauer - Introducing Vala Programming

One of the main factors that play into the run-time and build-time performance of a program written in a certain programming language is the languages level of abstraction . Low-level programming languages support a direct mapping of instructions to machine code (the native language to the CPU). This results in a speedy run-time performance but generally requires a higher implementation effort. Examples for languages with a low level of abstraction are C and Assembler, they belong to the oldest programming languages.

The widespread use of computer programs in almost every aspect of human life has lead to an increasing complexity of software systems. In light of the rapid advances in processing power, this complexity can be handled by creating higher levels of abstractions in programming languages. High-level programming languages allow to formulate algorithms in a more natural way, reducing the time to solve a problem and making it easier to read, understand, debug, and maintain. Considering that the programming costs are often a major factor when creating a new software system, this allows for significant economic advantages. Examples for languages with a high level of abstraction are Python and Rubyalso called scripting languages or sometimes 4GLs (fourth-generation languages).

A high level of abstraction comes with a more complex translation of a programs source code into machine codeinstructions can no longer be directly mapped, but even simple statements can lead to tens, hundreds, or even thousands of generated machine code instructions. Writing compilers for such languages is a complex task. A way to simplify this is to use the interpreter concept, where a program no longer gets directly translated into machine code but into an intermediate representation, sometimes called bytecode, which then gets executed by a special programan interpreter or a virtual machine (VM).

Compared to a real CPU, a virtual machine, such as the JAVA virtual machine (JVM), provides an execution environment at a much higher levelon the expense of a slower run-time and increased memory requirements.

This situation gets tightened with the vast success of todays mobile platforms, such as smartphones, tablets, or smart home gadgets for the Internet of Things (IOT). In contrast to stationary systems, mobile systems come with severe resource constraints. Battery efficiency is very important. On the other hand though, any recent (networked) GUI application contains an intrinsic level of complexity that is best handled by employing a programming language with a sufficiently high abstraction level.