simplified the instruction set but still no cigar

Author: YoEight

geth-eventql/src/codegen.rs

@@ -1,9 +1,9 @@
 use crate::{
     Expr, ExprVisitor, Literal, NodeAttributes, Operation, Query, QueryVisitor, Subject, Var,
-    parser::Record,
+    Where, parser::Record,
 };
 
-trait IntoLiteral {
+pub trait IntoLiteral {
     fn into_literal(self) -> Literal;
 }
 
@@ -44,144 +44,66 @@ impl IntoLiteral for usize {
 }
 
 pub enum Instr {
-    EnterScope,
-    ExitScope,
     Push(Literal),
-    EnterSource,
-    ExitSource,
     LoadVar,
-    LoadSource,
     Operation(Operation),
     Array,
-    Rec(usize),
-    Call(String),
+    Rec,
+    Call,
 }
 
 impl Instr {
-    pub fn push(value: impl IntoLiteral) -> Self {
+    pub fn lit(value: impl IntoLiteral) -> Self {
         Instr::Push(value.into_literal())
     }
 }
 
-pub enum SourceKind {
-    Events,
-    Subject,
-    Subquery,
-}
-
-pub struct LoadSource {
-    binding: String,
-    scope: u64,
-}
+pub fn codegen_where_clause(where_clause: &Where) -> Vec<Instr> {
+    let mut state = ExprCodegen::default();
 
-pub fn codegen(query: &Query) -> Vec<Instr> {
-    let mut state = Codegen::default();
-
-    query.dfs_post_order(&mut state);
+    where_clause.expr.dfs_post_order(&mut state);
 
     state.instrs
 }
 
 #[derive(Default)]
-pub struct Codegen {
+pub struct ExprCodegen {
     instrs: Vec<Instr>,
 }
 
-impl QueryVisitor for Codegen {
-    type Inner<'a> = ExprCodegen<'a>;
-
-    fn enter_query(&mut self, attrs: &NodeAttributes) {
-        self.instrs.push(Instr::push(attrs.scope));
-        self.instrs.push(Instr::EnterScope);
-    }
-
-    fn enter_from(&mut self, attrs: &NodeAttributes, _ident: &str) {
-        self.instrs.push(Instr::push(attrs.scope));
-        self.instrs.push(Instr::EnterSource);
-    }
-
-    fn on_source_events(&mut self, attrs: &NodeAttributes, ident: &str) {
-        self.instrs.push(Instr::push(attrs.scope));
-        self.instrs.push(Instr::push(ident));
-        self.instrs.push(Instr::push(0i64));
-        self.instrs.push(Instr::LoadSource);
+impl ExprVisitor for ExprCodegen {
+    fn on_literal(&mut self, _attrs: &NodeAttributes, lit: &Literal) {
+        self.instrs.push(Instr::Push(lit.clone()));
     }
 
-    fn on_source_subject(&mut self, attrs: &NodeAttributes, ident: &str, subject: &Subject) {
-        self.instrs.push(Instr::push(attrs.scope));
-        self.instrs.push(Instr::push(ident));
-        for seg in subject.inner.iter() {
-            self.instrs.push(Instr::push(seg));
+    fn on_var(&mut self, _attrs: &NodeAttributes, var: &Var) {
+        for seg in var.path.iter().rev() {
+            self.instrs.push(Instr::lit(seg));
         }
 
-        self.instrs.push(Instr::push(subject.inner.len()));
+        self.instrs.push(Instr::lit(var.path.len() + 1));
         self.instrs.push(Instr::Array);
-        self.instrs.push(Instr::push(1i64));
-        self.instrs.push(Instr::LoadSource);
-    }
-
-    fn on_source_subquery(&mut self, attrs: &NodeAttributes, ident: &str) -> bool {
-        self.instrs.push(Instr::push(attrs.scope));
-        self.instrs.push(Instr::push(ident));
-        self.instrs.push(Instr::push(2i64));
-        self.instrs.push(Instr::LoadSource);
-
-        true
-    }
-
-    fn exit_from(&mut self, attrs: &NodeAttributes, ident: &str) {
-        self.instrs.push(Instr::push(attrs.scope));
-        self.instrs.push(Instr::ExitSource);
-    }
-
-    fn exit_query(&mut self) {
-        self.instrs.push(Instr::ExitScope);
+        self.instrs.push(Instr::lit(var.name.as_str()));
+        self.instrs.push(Instr::LoadVar);
     }
 
-    fn expr_visitor<'a>(&'a mut self) -> Self::Inner<'a> {
-        ExprCodegen { inner: self }
-    }
-}
-
-pub struct ExprCodegen<'a> {
-    inner: &'a mut Codegen,
-}
-
-impl ExprVisitor for ExprCodegen<'_> {
-    fn on_literal(&mut self, _attrs: &NodeAttributes, lit: &Literal) {
-        self.inner.instrs.push(Instr::Push(lit.clone()));
-    }
-
-    fn on_var(&mut self, attrs: &NodeAttributes, var: &Var) {
-        self.inner.instrs.push(Instr::push(attrs.scope));
-
-        self.inner.instrs.push(Instr::push(var.name.as_str()));
-        for seg in &var.path {
-            self.inner.instrs.push(Instr::push(seg));
+    fn exit_record(&mut self, _attrs: &NodeAttributes, record: &Record) {
+        for key in record.fields.keys() {
+            self.instrs.push(Instr::lit(key));
         }
 
-        self.inner.instrs.push(Instr::push(var.path.len() + 1));
-        self.inner.instrs.push(Instr::Array);
-        self.inner.instrs.push(Instr::LoadVar);
-    }
-
-    fn enter_record_entry(&mut self, _attrs: &NodeAttributes, key: &str, _expr: &Expr) {
-        self.inner
-            .instrs
-            .push(Instr::Push(Literal::String(key.to_string())));
-    }
-
-    fn exit_record(&mut self, _attrs: &NodeAttributes, record: &Record) {
-        self.inner.instrs.push(Instr::Rec(record.fields.len()));
+        self.instrs.push(Instr::lit(record.fields.len()));
+        self.instrs.push(Instr::Rec);
     }
 
     fn exit_array(&mut self, _attrs: &NodeAttributes, values: &[Expr]) {
-        self.inner.instrs.push(Instr::push(values.len()));
-        self.inner.instrs.push(Instr::Array);
+        self.instrs.push(Instr::lit(values.len()));
+        self.instrs.push(Instr::Array);
     }
 
     fn exit_app(&mut self, _attrs: &NodeAttributes, name: &str, _params: &[Expr]) {
-        self.inner.instrs.push(Instr::Call(name.to_string()));
+        self.instrs.push(Instr::lit(name));
+        self.instrs.push(Instr::Call);
     }
 
     fn exit_binary_op(
@@ -191,10 +113,10 @@ impl ExprVisitor for ExprCodegen<'_> {
         _lhs: &Expr,
         _rhs: &Expr,
     ) {
-        self.inner.instrs.push(Instr::Operation(*op));
+        self.instrs.push(Instr::Operation(*op));
     }
 
     fn exit_unary_op(&mut self, _attrs: &NodeAttributes, op: &Operation, _expr: &Expr) {
-        self.inner.instrs.push(Instr::Operation(*op));
+        self.instrs.push(Instr::Operation(*op));
     }
 }