http://blog.csdn.net/anghlq/article/details/6803332
ErLang语法约定：
- 大写字母开头的名字（比如Address），表示一个变量，包括参数、局部变量等；
- 小写字母开头的单词（比如ok），表示一个常量，叫做atom（原子的意思），包括常量名、函数名、模块名等。
- ErLang的注释用%开头。ErLang用下划线“_”表示任意变量，类似于Java的switch语法里面的default选项。
- 参数中没使用到的变量用下杠和首字母大写，如_Sample
比较符
| op | Description |
| == | equal to |
| /= | not equal to |
| =< | less than or equal to |
| < | less than |
| >= | greater than or equal to |
| > | greater than |
| =:= | exactly equal to |
| =/= | exactly not equal to |
1> 1==1.0. true 2> 1=:=1.0. false 运算符
| op | Description | Argument type |
| + | unary + | number |
| - | unary - | number |
| + | number | |
| - | number | |
| * | number | |
| / | floating point division | number |
| bnot | unary bitwise not | integer |
| div | integer division | integer |
| rem | integer remainder of X/Y | integer |
| band | bitwise and | integer |
| bor | bitwise or | integer |
| bxor | arithmetic bitwise xor | integer |
| bsl | arithmetic bitshift left | integer |
| bsr | bitshift right | integer |
7> 2#10 band 2#01. 0 8> 2#10 bor 2#01. 3
Boolean表达式
| op | Description |
| not | unary logical not |
| and | logical and |
| or | logical or |
| xor | logical xor |
短路表达式
Expr1 orelse Expr2
Expr1 andalso Expr2
case A >= -1.0 andalso math:sqrt(A+1) > B of
列表表达式
++
--
1> [1,2,3]++[4,5]. [1,2,3,4,5] 2> [1,2,3,2,1,2]--[2,1,2]. [3,1,2]
二进制表达式
<<>> <<E1,...,En>>
Ei = Value |
Value:Size |
Value/TypeSpecifierList |
Value:Size/TypeSpecifierList
- TypeSpecifierList
- Type= integer | float | binary | bytes |bitstring | bits | utf8 | utf16 | utf32
- Signedness= signed | unsigned
-
- Endianness= big | little | native
- Unit= unit:IntegerLiteral
11> <<G,H/bitstring>> = <<1,17,42:12>>. <<1,17,1,10:4>> 12> H. <<17,1,10:4>> 13> <<1024/utf8>>. <<208,128>>
- 赋值时注意增加空格 B=<<1>> 会变成语法错误，因为跟比较符号=<冲突、、
<<"--\r\n", Data/binary>>,
strchr(Bin, C, I) ->
case Bin of
<<_X:I/binary>> ->
0;
<<_X:I/binary, C, _Rest/binary>> ->
I+1;
_ ->
strchr(Bin, C, I+1)
end.
parse_boolean(Value) ->
case Value of
true -> true;
false -> false;
<<"true">> -> true;
<<"false">> -> false;
<<"1">> -> true;
<<"0">> -> false;
1 -> true;
0 -> false
end.
<<N1:32/integer, N2:32/float>> = Bin.
<< PointID:32/unsigned-little-integer, Value:32/little-float>> = Bin.
case Packet of
<<Len:16, PayLoad:Len/binary, 16#ef>> ->
{body, PayLoad};
_ ->
{error, invalid_packet}
end.
case Info of
<<"get ",Str1/bitstring>>->
io:format("case0:~s~n", [binary_to_list(Str1)]);
<<1:1,Str1/bitstring>>->
io:format("case1:~s~n", [Str1])
end.