59 lines
2.2 KiB
Markdown
59 lines
2.2 KiB
Markdown
# Introduction
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## Scope
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This is a tutorial for the Rust programming language. It assumes the
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reader is familiar with the basic concepts of programming, and has
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programmed in one or more other languages before. The tutorial covers
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the whole language, though not with the depth and precision of the
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[language reference][1].
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FIXME: maybe also the stdlib?
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[1]: http://www.rust-lang.org/doc/rust.html
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## Disclaimer
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Rust is a language under development. The general flavor of the
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language has settled, but details will continue to change as it is
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further refined. Nothing in this tutorial is final, and though we try
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to keep it updated, it is possible that the text occasionally does not
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reflect the actual state of the language.
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## First Impressions
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Though syntax is something you get used to, an initial encounter with
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a language can be made easier if the notation looks familiar. Rust is
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a curly-brace language in the tradition of C, C++, and JavaScript.
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fn fac(n: int) -> int {
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let result = 1, i = 1;
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while i <= n {
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result *= i;
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i += 1;
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}
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ret result;
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}
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Several differences from C stand out. Types do not come before, but
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after variable names (preceded by a colon). In local variables
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(introduced with `let`), they are optional, and will be inferred when
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left off. Constructs like `while` and `if` do not require parenthesis
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around the condition (though they allow them). Also, there's a
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tendency towards aggressive abbreviation in the keywords—`fn` for
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function, `ret` for return.
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You should, however, not conclude that Rust is simply an evolution of
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C. As will become clear in the rest of this tutorial, it goes in
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quite a different direction.
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## Conventions
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Throughout the tutorial, words that indicate language keywords or
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identifiers defined in the example code are displayed in `code font`.
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Code snippets are indented, and also shown in a monospace font. Not
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all snippets constitute whole programs. For brevity, we'll often show
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fragments of programs that don't compile on their own. To try them
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out, you'll have to wrap them in `fn main() { ... }`, and make sure
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they don't contain references to things that aren't actually defined.
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