02-TICKscript语言-A-基础语法和运算符

TICKscript 语法

介绍

TICKscript语言是一种用于定义数据处理管道的调用链语言。

符号

使用Extended Backus-Naur Form（“EBNF”）指定语法。EBNF与Go编程语言规范中使用的符号相同，可在此处找到。

Production  = production_name "=" [ Expression ] "." .
Expression  = Alternative { "|" Alternative } .
Alternative = Term { Term } .
Term        = production_name | token [ "…" token ] | Group | Option | Repetition .
Group       = "(" Expression ")" .
Option      = "[" Expression "]" .
Repetition  = "{" Expression "}" .

符号运算符按优先顺序排列：

|   alternation
()  grouping
[]  option (0 or 1 times)
{}  repetition (0 to n times)

语法

以下是TICKscript的EBNF语法定义。

unicode_char        = (* an arbitrary Unicode code point except newline *) .
digit               = "0" … "9" .
ascii_letter        = "A" … "Z" | "a" … "z" .
letter              = ascii_letter | "_" .
identifier          = ( letter ) { letter | digit } .
boolean_lit         = "TRUE" | "FALSE" .
int_lit             = "1" … "9" { digit }
letter              = ascii_letter | "_" .
number_lit          = digit { digit } { "." {digit} } .
duration_lit        = int_lit duration_unit .
duration_unit       = "u" | "µ" | "ms" | "s" | "m" | "h" | "d" | "w" .
string_lit          = `'` { unicode_char } `'` .
star_lit            = "*"
regex_lit           = `/` { unicode_char } `/` .

operator_lit       = "+" | "-" | "*" | "/" | "==" | "!=" |
                     "<" | "<=" | ">" | ">=" | "=~" | "!~" |
                     "AND" | "OR" .

Program      = Statement { Statement } .
Statement    = Declaration | Expression .
Declaration  = "var" identifier "=" Expression .
Expression   = identifier { Chain } | Function { Chain } | Primary .
Chain        = "@" Function | "|" Function { Chain } | "." Function { Chain} | "." identifier { Chain } .
Function     = identifier "(" Parameters ")" .
Parameters   = { Parameter "," } [ Parameter ] .
Parameter    = Expression | "lambda:" LambdaExpr | Primary .
Primary      = "(" LambdaExpr ")" | number_lit | string_lit |
                boolean_lit | duration_lit | regex_lit | star_lit |
                LFunc | identifier | Reference | "-" Primary | "!" Primary .
Reference    = `"` { unicode_char } `"` .
LambdaExpr   =  Primary operator_lit Primary .
LFunc        = identifier "(" LParameters ")"
LParameters  = { LParameter "," } [ LParameter ] .
LParameter   = LambdaExpr |  Primary .

注释：通过//实现

关键字

Word Usage
TRUE The literal Boolean value “true”.
FALSE The literal Boolean value “false”.
AND 与
OR 或
lambda: lambda表达式
var 变量声明
dbrp 数据库声明

运算符

Operator Usage Examples
+ 加法和字符串连接 3 + 6, total + count and 'foo' + 'bar'
- 减法 10 - 1, total - errs
* 乘法 3 * 6, ratio * 100.0
/ 除法 36 / 4, errs / total
== 等值判断 1 == 1, date == today
!= 不等于判断 result != 0, id != "testbed"
< 小于判断 4 < 5, timestamp < today
<= 小于等于判断 3 <= 6, flow <= mean
> 大于判断 6 > 3.0, delta > sigma
>= 大于等于判断 9.0 >= 8.1, quantity >= threshold
=~ 正则匹配判断 tag =~ /^cz\d+/
!~ 正则不匹配判断 tag !~ /^sn\d+/
! 逻辑否定 !TRUE, !(cpu_idle > 70)
AND 逻辑与 rate < 20.0 AND rate >= 10
OR 逻辑或 status > warn OR delta > sigma

链接运算符

操作符 用法 例子
**\ ** 声明一个链接方法调用，它创建一个新节点的实例并将其链接到它上面的节点。 stream from()
. 声明属性方法调用，设置或更改它所属的节点中的内部属性。 from() .database(mydb)
@ 声明用户定义的函数（UDF）调用。本质上是一种链接方法，它将新的UDF节点添加到管道中。 from() ... @MyFunc()