feat: introduce jinja format rule

Author: benfdking

crates/lib/src/core/rules/base.rs

@@ -34,6 +34,7 @@ pub enum RuleGroups {
     Ambiguous,
     Capitalisation,
     Convention,
+    Jinja,
     Layout,
     References,
     Structure,

crates/lib/src/rules.rs

@@ -10,6 +10,7 @@ pub mod convention;
 pub mod layout;
 pub mod references;
 pub mod structure;
+pub mod jinja;
 
 pub fn rules() -> Vec<ErasedRule> {
     chain!(
@@ -19,7 +20,8 @@ pub fn rules() -> Vec<ErasedRule> {
         convention::rules(),
         layout::rules(),
         references::rules(),
-        structure::rules()
+        structure::rules(),
+        jinja::rules(),
     )
     .collect_vec()
 }

crates/lib/src/rules/jinja.rs

@@ -0,0 +1,7 @@
+pub mod jj01;
+
+pub fn rules() -> Vec<ErasedRule> {
+    use crate::core::rules::base::Erased as _;
+
+    vec![jj01::RuleJJ01::default().erased()]
+}

crates/lib/src/rules/jinja/jj01.rs

@@ -0,0 +1,72 @@
+use ahash::AHashMap;
+use sqruff_lib_core::dialects::syntax::{SyntaxKind, SyntaxSet};
+use sqruff_lib_core::parser::segments::base::SegmentBuilder;
+
+use crate::core::config::Value;
+use crate::core::rules::base::{Erased, ErasedRule, LintResult, Rule, RuleGroups};
+use crate::core::rules::context::RuleContext;
+use crate::core::rules::crawlers::{Crawler, SegmentSeekerCrawler};
+use crate::utils::reflow::sequence::{Filter, ReflowInsertPosition, ReflowSequence, TargetSide};
+
+#[derive(Debug, PartialEq, Eq, Clone, Copy)]
+pub enum Aliasing {
+    Explicit,
+    Implicit,
+}
+
+#[derive(Debug, Clone)]
+pub struct RuleJJ01 {
+}
+
+impl Rule for RuleJJ01 {
+    fn load_from_config(&self, _config: &AHashMap<String, Value>) -> Result<ErasedRule, String> {
+        Ok()
+    }
+
+    fn name(&self) -> &'static str {
+        "jinja.padding"
+    }
+
+    fn description(&self) -> &'static str {
+        "Jinja tags should have a single whitespace on either side."
+    }
+
+    fn long_description(&self) -> &'static str {
+        r#"
+**Anti-pattern**
+
+Jinja tags with either no whitespace or very long whitespace are hard to read.
+
+```sql
+SELECT {{    a     }} from {{ref('foo')}}
+```
+
+**Best practice**
+
+A single whitespace surrounding Jinja tags, alternatively longer gaps containing newlines are acceptable.
+
+```sql
+SELECT {{ a }} from {{ ref('foo') }};
+SELECT {{ a }} from {{
+     ref('foo')
+}};
+```
+"#
+    }
+
+    fn groups(&self) -> &'static [RuleGroups] {
+        &[RuleGroups::All, RuleGroups::Jinja]
+    }
+
+    fn eval(&self, rule_cx: &RuleContext) -> Vec<LintResult> {
+        unimplemented!()
+    }
+
+    fn is_fix_compatible(&self) -> bool {
+        true
+    }
+
+    fn crawl_behaviour(&self) -> Crawler {
+        SegmentSeekerCrawler::new(const { SyntaxSet::new(&[SyntaxKind::AliasExpression]) }).into()
+    }
+}