dimgigov
e1bae0c7a0
- Add docs/ folder with English (en/) and Bulgarian (bg/) documentation - Create index.md with language switching and links - English docs: installation, quickstart, architecture, baraql, storage, schema, lsm, btree, vector, graph, fts, columnar, transactions, distributed, protocol, udf, api-binary, api-http, api-websocket - Bulgarian docs: installation, quickstart, architecture, baraql, schema, lsm, btree, vector, graph, fts, transactions, distributed - Update README license to BSD 3-Clause - Add LICENSE file with BSD 3-Clause text
56 lines
1.5 KiB
Markdown
56 lines
1.5 KiB
Markdown
# User Defined Functions
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Extend BaraQL with custom functions.
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## Usage
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```nim
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import barabadb/query/udf
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var reg = newUDFRegistry()
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# Register standard library
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reg.registerStdlib() # abs, sqrt, pow, lower, upper, len, trim, substr, toString, toInt
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# Custom function
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reg.register("greet", @[UDFParam(name: "name", typeName: "str")],
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"str", proc(args: seq[Value]): Value =
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return Value(kind: vkString, strVal: "Hello, " & args[0].strVal & "!"))
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```
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## Standard Library Functions
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| Function | Description | Example |
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|----------|-------------|---------|
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| `abs(n)` | Absolute value | `abs(-5)` → 5 |
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| `sqrt(n)` | Square root | `sqrt(16)` → 4 |
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| `pow(n, e)` | Power | `pow(2, 3)` → 8 |
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| `lower(s)` | Lowercase | `lower('ABC')` → 'abc' |
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| `upper(s)` | Uppercase | `upper('abc')` → 'ABC' |
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| `len(s)` | Length | `len('hello')` → 5 |
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| `trim(s)` | Trim whitespace | `trim(' hello ')` → 'hello' |
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| `substr(s, start, len)` | Substring | `substr('hello', 0, 3)` → 'hel' |
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| `toString(n)` | Convert to string | `toString(123)` → '123' |
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| `toInt(s)` | Convert to integer | `toInt('123')` → 123 |
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## Function Registration
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```nim
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reg.register(
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name: "my_function",
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params: @[
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UDFParam(name: "arg1", typeName: "str"),
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UDFParam(name: "arg2", typeName: "int32")
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],
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returnType: "str",
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body: proc(args: seq[Value]): Value =
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# Implementation
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result = Value(kind: vkString, strVal: "")
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)
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```
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## Using UDFs in Queries
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```sql
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SELECT greet(name) FROM users;
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``` |