Initial commit

Slang.md

@@ -0,0 +1,170 @@
+# Slang 
+<!-- <font size=0>(June, 30 12:04 AM draft)</font> -->
+
+### Example code
+<!-- TODO: Slang syntax highlighting -->
+```c
+# this is a comment
+#| and that is a
+	multiline one. |#
+
+const u32 n = 123123  # n is of type const u32
+const i64 m = 10**18  # m is of type const i64
+const int z = 2**128  # z is of type const int (unsized)
+const auto q = 2**256  # q is of type const int
+
+char f(str x) {  # f() is of type char, x is of type str
+	auto c = x[1]  # c is of type char
+	return c
+}
+
+char g(str x) {  # g() is of type char, x is of type str
+	return x[0]  # retval is of type char
+}
+
+int h(int x) = x+1  # h() is of type int, x is of type int
+
+void main() {
+	print(h(n), \
+		f('123asd') + g('32') + 1)  #--> «123124 f»
+	print(q/z/2**96)  #--> «4294967296.0»
+}
+
+main()
+```
+
+## Tokens
+
+* [Keywords](#Keywords)
+* [Identifiers](#Identifiers)
+* [Literals](#Literals)
+* [Operators](#Operators)
+* [Specials](#Specials)
+
+#### Token resolution order
+
+1. Special
+2. Operator
+3. Literal
+4. Keyword
+5. Identifier
+
+## Syntax structures
+
+_Note: `*` after syntax unit means any number of them._
+
+### Abstract
+
+* `{[<\n | ;>]* <<expr> <\n | ;>>* [<\n | ;>]*}` — `code`
+* `<<expr> | <code>>` — `block`
+
+### Primitive
+
+* `<<literal> | <funccall> | <attrget> | <itemget> | <identifier> | <lambda>>` — `value`
+* `<value>\[<value>\]` — `itemget`
+* `<(<expr>) | <value> | <operator> <expr> | <expr> <operator> <expr>>` — `expr` (`f(x+3)` is an instance of `expr`, also `f`, `x+3` and `x` are `expr`s too)
+
+### Non-final
+
+* `[modifier]* <type>` — `typedef` (left-hand type definition)
+* `[typedef] <identifier> [? | + | * | ** | =<expr>]` — `argdef` (argument definition)
+ > `?` — if present then argument value, `none` else.<br>
+ > `+` — tuple with at least one argument.<br>
+ > `*` — tuple with any number of arguments.<br>
+ > `**` — object with keyword arguments.<br>
+ > `=` — default value if argument not specified.
+* `([<argdef>[, <argdef>]*]) -> <typedef> = <expr>` — `lambda` (lambda function)
+* `<<expr>[, <expr>]*[, *<expr>] | *<expr>>` — `callargs`
+* `<<identifier>=<expr>[, <identifier>=<expr>]*[, **<expr>] | **<expr>>` — `callkwargs`
+
+### Final (ordered by resolution order)
+
+* `<typedef> <identifier>([<argdef>[, <argdef>]*]) <<code> | = <expr>>` — `funcdef` (function definition)
+* `<exprkeyword> [expr]` — `keywordexpr` (keyword expression)
+* `<typedef> <identifier> [= <value>]` — `vardef` (variable definition)
+* `<identifier> = <value>` — `assignment`
+* `<value>([<callargs> | <callkwargs> | <callargs>, <callkwargs>])` — `funccall` (function call)
+* `<expr>` — expr evaluation (only in REPL)
+* `if (<expr>) <block>` — `conditional`
+* `for (<identifier> in <expr>) <block>` — `forloop`
+* `while (<expr>) <block>` — `whileloop`
+* `else <block>` — `elseclause`
+
+## Keywords
+
+* `return [expr]` — return from function
+
+### Modifiers
+
+* `const` — immutable/constant variable
+
+### Reserved keywords
+
+* `def`
+
+## Identifiers
+
+Non-empty sequence of alphanumeric characters plus underscore («_»), not starting with a digit character.
+
+Regex: `[_\w]+[_\w\d]*`
+
+### Data types
+
+* `i8`, `i16`, `i32`, `i64`, `i128` — fixed size integer
+* `u8`, `u16`, `u32`, `u64`, `u128` — fixed size unsigned integer
+* `f8`, `f16`, `f32`, `f64`, `f128` — fixed size IEEE-754 floating point number
+* `uf8`, `uf16`, `uf32`, `uf64`, `uf128` — fixed size unsigned floating point number
+* `int` — unsized («big») integer
+* `uint` — unsized unsigned integer
+* `float` — unsized floating point number
+* `ufloat` — unsized unsigned floating point
+* `bool` — logical (boolean) value
+* `byte` — single byte
+* `char` — UTF-8 character
+* `str` — UTF-8 string
+* `void` — nothing (or anything...)
+
+* `auto` — compile-time type deduction based on value
+
+## Literals
+
+_Note: `*` after syntax unit here means any number of them, `+` means at least one._
+
+* `<<0<b | o | x>><digit+> | <digit+>.<digit*> | <digit*>.<digit+>>` — number
+* `<"<character*>" | '<character*>'>` — string
+
+## Operators
+
+* `<operator> <operand>` — unary operators usage
+* `<operand> <operator> <operand>` — binary operators usage
+* `<operand> <operator>= <operand>` — in-place operator usage
+
+### Character operators
+
+A set of pre-defined character operators:
+
+* `!$%&*+-:^~` — unary charset
+* `%&*+-/<=>^|` — binary charset
+* `==`, `**`, `//`, `<<`, `>>` — double-char binary operators
+
+### Keyword operators
+
+A set of pre-defined keyword operators:
+
+* `not` — unary keyword operator
+* `and`, `or`, `xor`, `is`, `is not`, `to` — binary keyword operators
+
+## Specials
+
+* `#`, `#|`, `|#` — comment specials
+* `;` — expr separator special
+* `->`, `@.`, `@`, `.`, `:` — attrget optype specials
+* `[`, `]` — itemget specials
+* `\,?=(){}` — other specials charset
+
+# Footnotes
+
+All character class checks are performed in current locale.
+
+---
+_by Sdore, 2019_