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+
+ Soml is a language that is designed to be compiled into, rather than written, like
+ other languages. It is the base for a higher system,
+ designed for the needs to compile ruby. It is not an endeavour to abstract from a
+ lower level, like other system languages, namely off course c.
+ Still it is a system language, or an object machine language, so almost as low level a
+ language as possible. Only assembler is really lower, and it could be argued that assembler
+ is not really a language, rather a data format for expressing binary code.
+
+ Soml is completely object oriented and strongly typed. For types, the classes are used, but + the main distinction is between object (references) and integers. This is off course + essential as dereferencing integers is what we want to avoid. +
+
+ The object model, ie the basic properties of objects that the system relies on, is quite simple
+ and explained below. It involves a single reference per object.
Also the object memory
+ model is kept quite simple in that objects are always small multiples of the cache size of the
+ hardware machine. We use object encapsulation to build up larger looking objects from these
+ basic blocks.
+
+ The calling convention is also object oriented, not stack based*. Message objects used to + define the data needed for invocation. They carry arguments, a frame and return addresses. + In Soml return addresses are pre-calculated and determined by the caller, and yes, there + are several. In fact there is one return address per masic type, plus one for exception. + A method invocation may thus be made to return to an entirely different location than the + caller. + *(A stack, as used in c, is not typed and as such a source of problems) +
++ There is no non- object based memory in soml. The only global constants are instances of + classes that can be accessed by writing the class name in soml source. +
+
+ Soml syntax is a mix between ruby and c. I is like ruby in the sense that semicolons and even
+ newlines are not neccessary unless they are. It still uses braces, but that will probably
+ be changed.
+ But off course it is typed, so in argument or variable definitions the type must be specified
+ like in c. Types are classes, but int may be used for brevity instead of Integer. Return
+ types are also declared, though more for statci analysis. As mentioned any function may return
+ to differernt addresses according to type. The compiler automatically inserts erros for
+ return typesa that are not handled by the caller.
+ The complete syntax and their translation is discussed here
+
+ As soml is the base for dynamic languages, all compile information is recorded in the runtime.
+ All inforamtion is off course object oriented, ie in the form off objects. This means a class
+ hierachy and this itself is off course part of the runtime. The runtime, Parfait, is kept
+ to a minnimum, currently around 15 classes, described in detail
+ here .
+ Historically Parfait has been coded in ruby, as it was first needed in the compiler.
+ This had the additional benefit of providing solid test cases for the functionality.
+ Currently the process is to recode the same functionality in soml, and by the end of that
+ a converter will be written. This will convert the soml code into ruby code, thus removing the
+ duplication.
+