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use derive_builder::Builder; use crate::{ToQueryString, IndentedString}; use itertools::Itertools; use crate::condition::Condition; #[derive(Clone)] pub enum Predicate { Count(Field), Field(Field), Edge(Edge), Val(Variable), ScalarVariable(String, Field), EdgeVariable(String, Edge) } #[derive(Clone, Debug)] pub struct Variable { name: String, alias: Option<String> } impl Variable { pub fn new(name: &str) -> Self { Self { name: name.to_string(), alias: None } } pub fn alias(mut self, alias: &str) -> Self { self.alias = Some(alias.to_string()); self } pub fn random() -> Self { Self::new(&format!("var_{}", rand::random::<u128>())) } pub fn get_name(&self) -> String { self.name.clone() } fn get_alias(&self) -> String { self.alias.clone() .map(|alias| format!("{} : ", alias)) .unwrap_or("".to_string()) } } #[derive(Clone)] pub struct Field { name: String, alias: Option<String> } impl Field { pub fn new(name: &str) -> Self { Self { name: name.to_string(), alias: None } } pub fn alias(mut self, alias: &str) -> Self { self.alias = Some(alias.to_string()); self } fn get_alias(&self) -> String { self.alias.clone() .map(|alias| format!("{} : ", alias)) .unwrap_or("".to_string()) } } #[derive(Builder, Clone)] pub struct Edge { name: String, predicates: Vec<Predicate>, #[builder(setter(strip_option), default)] filter: Option<Condition>, #[builder(setter(strip_option), default)] alias: Option<String> } impl Edge { fn get_alias(&self) -> String { self.alias.clone() .map(|alias| format!("{} : ", alias)) .unwrap_or("".to_string()) } } impl ToQueryString for Edge { fn to_query_string(&self) -> String { let predicates = self.predicates.iter() .map(|predicate| predicate.to_query_string()) .join("\n"); let filter = self.filter.clone() .map(|filter| format!(" @filter({})", filter.to_query_string())) .unwrap_or("".to_string()); format!("\ {alias}{name}{filter} {{\n\ {predicates}\n\ }}", alias = self.get_alias(), name = self.name, filter = filter, predicates = predicates.indent()) } } impl ToQueryString for Predicate { fn to_query_string(&self) -> String { match self { Predicate::Field(field) => { format!("{alias}{name}", alias = field.get_alias(), name = field.name) }, Predicate::Val(variable) => { format!("{alias}val({name})", alias = variable.get_alias(), name = variable.name) }, Predicate::EdgeVariable(name, edge) => { format!("{name} as {edge}", name = name, edge = edge.to_query_string()) }, Predicate::ScalarVariable(name, field) => { format!("{name} as {field}", name = name, field = field.name) }, Predicate::Count(field) => { format!("{alias}count({name})", alias = field.get_alias(), name = field.name) }, Predicate::Edge(edge) => { format!("{edge}", edge = edge.to_query_string()) } } } }