Struct CustomDialectBuilder 

pub struct CustomDialectBuilder { /* private fields */ }

Fluent builder for creating and registering custom SQL dialects.

A custom dialect is based on an existing built-in dialect and allows selective overrides of tokenizer configuration, generator configuration, and expression transforms.

Example

use polyglot_sql::dialects::{CustomDialectBuilder, DialectType, Dialect};
use polyglot_sql::generator::NormalizeFunctions;

CustomDialectBuilder::new("my_postgres")
    .based_on(DialectType::PostgreSQL)
    .generator_config_modifier(|gc| {
        gc.normalize_functions = NormalizeFunctions::Lower;
    })
    .register()
    .unwrap();

let d = Dialect::get_by_name("my_postgres").unwrap();
let exprs = d.parse("SELECT COUNT(*)").unwrap();
let sql = d.generate(&exprs[0]).unwrap();
assert_eq!(sql, "select count(*)");

polyglot_sql::unregister_custom_dialect("my_postgres");

Implementations

impl CustomDialectBuilder

pub fn new(name: impl Into<String>) -> Self

Create a new builder with the given name. Defaults to Generic as the base dialect.

pub fn based_on(self, dialect: DialectType) -> Self

Set the base built-in dialect to inherit configuration from.

pub fn tokenizer_config_modifier<F>(self, f: F) -> Self

where F: FnOnce(&mut TokenizerConfig) + 'static,

Provide a closure that modifies the tokenizer configuration inherited from the base dialect.

pub fn generator_config_modifier<F>(self, f: F) -> Self

where F: FnOnce(&mut GeneratorConfig) + 'static,

Provide a closure that modifies the generator configuration inherited from the base dialect.

pub fn transform_fn<F>(self, f: F) -> Self

where F: Fn(Expression) -> Result<Expression> + Send + Sync + 'static,

Set a custom per-node expression transform function.

This replaces the base dialect’s transform. It is called on every expression node during the recursive transform pass.

pub fn preprocess_fn<F>(self, f: F) -> Self

where F: Fn(Expression) -> Result<Expression> + Send + Sync + 'static,

Set a custom whole-tree preprocessing function.

This replaces the base dialect’s built-in preprocessing. It is called once on the entire expression tree before the recursive per-node transform.

pub fn register(self) -> Result<()>

Build the custom dialect configuration and register it in the global registry.

Returns an error if:

• The name collides with a built-in dialect name
• A custom dialect with the same name is already registered