intro.dd

Ddoc

$(SPEC_S Introduction,

	$(P The D programming language is a general purpose systems programming language.
	To that end, a D program is a collection of modules that can be compiled separately
	to native code that is combined with libraries and compiled C code by a linker to create a
	native executable.
	)

$(H3 Phases of Compilation)

	The process of compiling is divided into multiple phases. Each phase
	has no dependence on subsequent phases. For example, the scanner is
	not perturbed by the semantic analyzer. This separation of the passes
	makes language tools like syntax
	directed editors relatively easy to produce.
	It also is possible to compress D source by storing it in
	$(SINGLEQUOTE tokenized) form.

$(OL
	$(LI $(B source character set)$(BR)

	The source file is checked to see what character set it is,
	and the appropriate scanner is loaded. ASCII and UTF
	formats are accepted.
	)

	$(LI $(B script line) $(BR)

	If the first line starts with $(GREEN #!) then the first line
	is ignored.
	)

	$(LI $(B lexical analysis)$(BR)

	The source file is divided up into a sequence of tokens.
	$(DDSUBLINK lex, specialtokens, Special tokens))
	are replaced with other tokens.
	$(GLINK2 lex, SpecialTokenSequence)s
	are processed and removed.
	)

	$(LI $(B syntax analysis)$(BR)

	The sequence of tokens is parsed to form syntax trees.
	)

	$(LI $(B semantic analysis)$(BR)

	The syntax trees are traversed to declare variables, load symbol tables, assign
	types, and in general determine the meaning of the program.
	)

	$(LI $(B optimization)$(BR)

	Optimization is an optional pass that tries to rewrite the program
	in a semantically equivalent, but faster executing, version.
	)

	$(LI $(B code generation)$(BR)

	Instructions are selected from the target architecture to implement
	the semantics of the program. The typical result will be
	an object file, suitable for input to a linker.
	)
)



)

Macros:
	TITLE=Introduction
	WIKI=SpecIntro
        CATEGORY_SPEC=$0