Refactor Parsing -> Compiling
Signed-off-by: Will Hawkins <hawkinsw@obs.cr>
This commit is contained in:
Will Hawkins
@@ -0,0 +1,451 @@
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// p4rse, Copyright 2026, Will Hawkins
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//
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// This file is part of p4rse.
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//
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// This file is free software: you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with this program. If not, see <https://www.gnu.org/licenses/>.
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import Common
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import P4Lang
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import P4Runtime
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import SwiftTreeSitter
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import TreeSitterExtensions
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import TreeSitterP4
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let p4lang = Language(tree_sitter_p4())
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public func ErrorOnNode(node: Node, withError error: String) -> Error {
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return Error(withMessage: "\(node.range): \(error)")
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}
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extension ParserAssignmentStatement: CompilableStatement {
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public static func Compile(
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node: Node, inTree tree: MutableTree, withScopes scopes: LexicalScopes
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) -> Result<(EvaluatableStatement, LexicalScopes)> {
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if node.nodeType != "assignmentStatement" {
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return Result.Error(
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ErrorOnNode(node: node, withError: "Did not find expected assignment statement"))
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}
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guard let lvalue_node = node.child(at: 0),
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lvalue_node.nodeType == "expression"
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else {
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return Result.Error(
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ErrorOnNode(node: node, withError: "Missing lvalue in assignment statement"))
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}
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guard let rvalue_node = node.child(at: 2),
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rvalue_node.nodeType == "expression"
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else {
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return Result.Error(
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ErrorOnNode(node: node, withError: "Missing rvalue in assignment statement"))
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}
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let maybe_parsed_rvalue = Expression.Compile(node: rvalue_node, inTree: tree, withScopes: scopes)
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guard case Result.Ok(let rvalue) = maybe_parsed_rvalue else {
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return Result.Error(maybe_parsed_rvalue.error()!)
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}
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let maybe_parsed_lvalue = LValue.Compile(node: lvalue_node, inTree: tree, withScopes: scopes)
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guard case .Ok(let lvalue_identifier) = maybe_parsed_lvalue else {
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return Result.Error(maybe_parsed_lvalue.error()!)
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}
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guard case Result.Ok(let lvalue_type) = scopes.lookup(identifier: lvalue_identifier) else {
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return Result.Error(
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ErrorOnNode(
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node: lvalue_node,
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withError: "Cannot assign to variable \(lvalue_identifier) not in scope"))
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}
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if rvalue.type().eq(rhs: lvalue_type) {
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return Result.Ok(
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(
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ParserAssignmentStatement(
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withLValue: TypedIdentifier(name: lvalue_node.text!, withType: lvalue_type),
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withValue: rvalue
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), scopes
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))
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} else {
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return Result.Error(
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ErrorOnNode(
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node: node,
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withError:
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"Cannot assign value of type \(rvalue.type()) to \(lvalue_identifier) (with type \(lvalue_type))"
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))
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}
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}
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}
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public struct Parser {
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public struct LocalElements {
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static func Compile(
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node: Node, inTree tree: MutableTree, withScope scopes: LexicalScopes
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) -> Result<(EvaluatableStatement, LexicalScopes)> {
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let localElementsParsers: [String: CompilableStatement.Type] = [
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"variableDeclaration": VariableDeclarationStatement.self
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]
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guard let parser = localElementsParsers[node.nodeType ?? ""] else {
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return Result.Error(
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ErrorOnNode(
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node: node, withError: "Unparseable statement type (\(node.nodeType))"))
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}
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switch parser.Compile(node: node, inTree: tree, withScopes: scopes) {
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case Result.Ok(let (parsed, parsed_updated_scopes)):
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return Result.Ok((parsed, parsed_updated_scopes))
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case Result.Error(let e):
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return Result.Error(Error(withMessage: "Failed to parse local element: \(e)"))
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}
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}
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}
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public struct Statement {
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static func Compile(
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node: Node, inTree tree: MutableTree, withScope scopes: LexicalScopes
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) -> Result<(EvaluatableStatement, LexicalScopes)> {
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if node.nodeType != "parserStatement" && node.nodeType != "statement" {
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return Result.Error(ErrorOnNode(node: node, withError: "Missing expected parser statement"))
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}
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let statement = node.child(at: 0)!
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let statementParsers: [String: CompilableStatement.Type] = [
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"assignmentStatement": ParserAssignmentStatement.self,
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"expressionStatement": ExpressionStatement.self,
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"variableDeclaration": VariableDeclarationStatement.self,
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"conditionalStatement": ConditionalStatement.self, "blockStatement": BlockStatement.self,
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]
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// Iterate through statement parsers and give each one a chance.
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guard let parser = statementParsers[statement.nodeType ?? ""] else {
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return Result.Error(
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ErrorOnNode(
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node: statement, withError: "Unparseable statement type (\(statement.nodeType))"))
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}
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switch parser.Compile(node: statement, inTree: tree, withScopes: scopes) {
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case Result.Ok(let (parsed, updatedLexicalScopes)):
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return .Ok((parsed, updatedLexicalScopes))
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case Result.Error(let e):
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return .Error(
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ErrorOnNode(node: node, withError: "Failed to parse a statement element: \(e)"))
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}
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}
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}
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public struct TransitionSelectExpressionCaseStatement {
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static func Compile(
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node: Node, inTree tree: MutableTree, withLexicalScopes scopes: LexicalScopes
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) -> Result<(KeysetExpression, LexicalScopes)> {
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if node.nodeType != "selectCase" {
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return Result.Error(Error(withMessage: "Expected select case not found"))
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}
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guard let keysetexpression_node = node.child(at: 0),
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keysetexpression_node.nodeType == "keysetExpression"
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else {
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return Result.Error(Error(withMessage: "Missing keyset expression in select case"))
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}
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guard let targetstate_node = node.child(at: 2),
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targetstate_node.nodeType == "identifier"
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else {
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return Result.Error(Error(withMessage: "Missing target state in select case"))
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}
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let maybe_parsed_keysetexpression = Expression.Compile(
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node: keysetexpression_node, inTree: tree, withScopes: scopes)
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guard case Result.Ok(let keysetexpression) = maybe_parsed_keysetexpression else {
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return Result.Error(maybe_parsed_keysetexpression.error()!)
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}
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let maybe_parsed_targetstate = Identifier.Compile(
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node: targetstate_node, inTree: tree, withScopes: scopes)
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guard case .Ok(let targetstate) = maybe_parsed_targetstate else {
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return Result.Error(maybe_parsed_targetstate.error()!)
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}
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return .Ok(
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(
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KeysetExpression(
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withKey: keysetexpression, withNextState: targetstate), scopes
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))
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}
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}
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public struct TransitionSelectExpression {
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static func Compile(
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node: Node, inTree tree: MutableTree, withScope scopes: LexicalScopes
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) -> Result<(ParserTransitionSelectExpression, LexicalScopes)> {
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guard
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let transition_selection_expression_query = try? SwiftTreeSitter.Query(
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language: p4lang,
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data: String(
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"(parserTransitionStatement (transition) (transitionSelectionExpression (selectExpression (select) (expression) @selector (selectBody) @body)))"
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).data(using: String.Encoding.utf8)!)
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else {
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return Result.Error(Error(withMessage: "Could not compile the tree sitter query"))
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}
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let qr = transition_selection_expression_query.execute(node: node, in: tree)
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guard let query_result = qr.next() else {
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return .Error(Error(withMessage: "Could not find transition select expression"))
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}
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let selector = query_result.captures(named: "selector")
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let body = query_result.captures(named: "body")
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if selector.isEmpty {
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return .Error(
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Error(withMessage: "Could not find transition select expression selector expression"))
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}
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let selector_node = selector[0].node
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let maybe_selector = Expression.Compile(node: selector_node, inTree: tree, withScopes: scopes)
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guard case .Ok(let selector) = maybe_selector else {
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return .Error(
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Error(
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withMessage:
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"Could not parse transition select expression selector expression: \(maybe_selector.error()!)"
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))
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}
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if body.isEmpty {
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return .Error(Error(withMessage: "Could not find transition select expression body"))
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}
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let body_node = body[0].node
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var kses: [KeysetExpression] = Array()
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var kses_errors: [Error] = Array()
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body_node.enumerateNamedChildren { current_node in
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let maybe_parsed_kse = TransitionSelectExpressionCaseStatement.Compile(
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node: current_node, inTree: tree, withLexicalScopes: scopes)
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if case .Ok((let parsed_kse, _)) = maybe_parsed_kse {
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kses.append(parsed_kse)
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} else {
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kses_errors.append(Error(withMessage: "\(maybe_parsed_kse.error()!)"))
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}
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}
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if !kses_errors.isEmpty {
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return .Error(
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Error(
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withMessage: "Error(s) parsing select cases: "
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+ (kses_errors.map { error in
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return "\(error.msg)"
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}.joined(separator: ";\n"))))
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}
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return .Ok(
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(
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ParserTransitionSelectExpression(withSelector: selector, withKeysetExpressions: kses),
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scopes
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))
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}
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}
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public struct TransitionStatement {
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static func Compile(
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node: Node, inTree tree: MutableTree, withScope scopes: LexicalScopes
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) -> Result<(ParserTransitionStatement, LexicalScopes)> {
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guard
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let next_state_query = try? SwiftTreeSitter.Query(
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language: p4lang,
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data: String(
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"(parserTransitionStatement (transition) (transitionSelectionExpression (identifier) @next-state))"
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).data(using: String.Encoding.utf8)!)
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else {
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return Result.Error(Error(withMessage: "Could not compile the tree sitter query"))
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}
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let qr = next_state_query.execute(node: node, in: tree)
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if let next_state_result = qr.next() {
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let transition_capture = next_state_result.captures(named: "next-state")
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let maybe_parsed_next_state = Identifier.Compile(
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node: transition_capture[0].node, inTree: tree, withScopes: scopes)
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if case .Ok(let next_state) = maybe_parsed_next_state {
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return .Ok(
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(ParserTransitionStatement(withNextState: next_state), scopes))
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} else {
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return .Error(
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Error(
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withMessage:
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"Could not parse the next state in a transition statement: \(maybe_parsed_next_state.error()!)"
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))
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}
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}
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return switch TransitionSelectExpression.Compile(node: node, inTree: tree, withScope: scopes) {
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case .Ok((let tse, _)):
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.Ok((ParserTransitionStatement(withTransitionExpression: tse), scopes))
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case .Error(let e): .Error(e)
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}
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}
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}
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public struct Statements {
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static func Compile(
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node: Node, inTree tree: MutableTree, withLexicalScopes scopes: LexicalScopes
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) -> Result<([EvaluatableStatement], LexicalScopes)> {
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if node.nodeType != "statements" && node.nodeType != "parserStatements" {
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return Result.Error(ErrorOnNode(node: node, withError: "Did not find expected statements"))
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}
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var parse_err: Error? = .none
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var current_scopes = scopes
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var parsed_s: [EvaluatableStatement] = Array()
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node.enumerateNamedChildren { node in
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switch Statement.Compile(
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node: node, inTree: tree, withScope: current_scopes)
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{
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case .Ok((let parsed_statement, let updated_scopes)):
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current_scopes = updated_scopes
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parsed_s.append(parsed_statement)
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case .Error(let e):
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parse_err = e
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}
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}
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if let parse_err = parse_err {
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return Result.Error(parse_err)
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}
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return Result.Ok((parsed_s, current_scopes))
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}
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}
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public struct State {
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static func Compile(
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node: Node, inTree tree: MutableTree, withLexicalScopes scopes: LexicalScopes
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) -> Result<(ParserState, LexicalScopes)> {
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var currentChildIdx = 1
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var currentChildIdxSafe = 2
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var currentChild: Node? = .none
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guard let node_type = node.nodeType,
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node_type == "parserState"
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else {
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return Result.Error(
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ErrorOnNode(node: node, withError: "Did not find a parser state declaration"))
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}
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if node.childCount < currentChildIdxSafe {
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return Result.Error(
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ErrorOnNode(node: node, withError: "Missing state name in state declaration"))
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}
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currentChild = node.child(at: 1)
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let maybe_state_identifier = Identifier.Compile(
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node: currentChild!, inTree: tree, withScopes: scopes)
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guard case Result.Ok(let state_identifier) = maybe_state_identifier else {
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return Result.Error(maybe_state_identifier.error()!)
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}
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// Skip the '{'
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currentChildIdx += 2
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currentChildIdxSafe += 2
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var parse_err: Error? = .none
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var current_scopes: LexicalScopes = LexicalScopes()
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var parsed_s: [EvaluatableStatement] = Array()
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if node.childCount < currentChildIdxSafe {
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return Result.Error(ErrorOnNode(node: node, withError: "Missing body of state declaration"))
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}
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currentChild = node.child(at: currentChildIdx)
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if currentChild!.nodeType == "parserStatements" {
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switch Statements.Compile(
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node: currentChild!, inTree: tree, withLexicalScopes: scopes.enter())
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{
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case .Ok(let (state_statements, updated_scopes)):
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parsed_s = state_statements
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current_scopes = updated_scopes
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case .Error(let error):
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parse_err = error
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}
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currentChildIdx += 1
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currentChildIdxSafe += 1
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}
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if let parse_err = parse_err {
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return Result.Error(parse_err)
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}
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if node.childCount < currentChildIdxSafe {
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return Result.Error(
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ErrorOnNode(node: node, withError: "Missing transition statement of state declaration"))
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}
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currentChild = node.child(at: currentChildIdx)
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switch TransitionStatement.Compile(
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node: currentChild!, inTree: tree, withScope: current_scopes)
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{
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case .Ok(let (transition_statement, new_scopes)):
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return Result.Ok(
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(
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ParserState(
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name: state_identifier, withStatements: parsed_s,
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withTransition: transition_statement), new_scopes
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))
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case .Error(let e): return .Error(e)
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}
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}
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}
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static func Compile(
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withName name: Common.Identifier, node: Node, inTree tree: MutableTree,
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withLexicalScopes scopes: LexicalScopes
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) -> Result<(P4Lang.Parser, LexicalScopes)> {
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guard
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let parser_state_query = try? SwiftTreeSitter.Query(
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language: p4lang,
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data: String(
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"(parserStates) @parser-states"
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).data(using: String.Encoding.utf8)!)
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else {
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return Result.Error(
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Error(withMessage: "Could not compile the parser state tree sitter query"))
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}
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var parser = P4Lang.Parser(withName: name)
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// Build a state from each one listed.
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let qr = parser_state_query.execute(node: node, in: tree)
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let qr_value = qr.next()!
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let captures = qr_value.captures(named: "parser-states")
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var error: Error? = .none
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var parser_scopes = scopes
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// TODO: Assert that there is only one.
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captures[0].node.enumerateChildren { parser_state in
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switch Parser.State.Compile(node: parser_state, inTree: tree, withLexicalScopes: scopes) {
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case Result.Ok(let (state, new_parser_scopes)):
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parser.states = parser.states.append(state: state)
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parser_scopes = new_parser_scopes
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case Result.Error(let e): error = e
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}
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}
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if let error = error {
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return .Error(error)
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}
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return Result.Ok((parser, parser_scopes))
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}
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}
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