From 8de9bd86d6480a124d6d7788fd3168960642bdb0 Mon Sep 17 00:00:00 2001
From: brettlangdon <brett@blangdon.com>
Date: Sat, 19 Sep 2015 09:38:42 -0400
Subject: [PATCH] get working on the parser

---
 parser/parser.go | 104 ++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 99 insertions(+), 5 deletions(-)

diff --git a/parser/parser.go b/parser/parser.go
index 3af6d79..6cf1086 100644
--- a/parser/parser.go
+++ b/parser/parser.go
@@ -10,8 +10,8 @@ import (
 )
 
 type Parser struct {
-	tokenizer *scanner.Scanner
-
+	Errors      []*Error
+	tokenizer   *scanner.Scanner
 	tokenBuffer []*token.Token
 }
 
@@ -30,6 +30,92 @@ func (parser *Parser) unreadToken(tok *token.Token) {
 	parser.tokenBuffer = append(parser.tokenBuffer, tok)
 }
 
+func (parser *Parser) addError(msg string) {
+	parser.Errors = append(parser.Errors, &Error{
+		Message: msg,
+	})
+}
+
+func (parser *Parser) expect(tokID token.TokenID) {
+	next := parser.nextToken()
+	if next.ID != tokID {
+		msg := "Unexpected token \"" + next.ID.String() + "\" expected \"" + tokID.String() + "\""
+		parser.addError(msg)
+	}
+}
+
+// compound_stmt: if_stmt | while_stmt | for_stmt | try_stmt | with_stmt | funcdef | classdef | decorated | async_stmt
+func (parser *Parser) parseCompoundStatement() *ast.CompoundStatement {
+	compoundStmt := ast.NewCompoundStatement()
+	return compoundStmt
+}
+
+// expr_stmt: testlist_star_expr (augassign (yield_expr|testlist) |
+//                      ('=' (yield_expr|testlist_star_expr))*)
+func (parser *Parser) parseExpressionStatement() *ast.ExpressionStatement {
+	exprStmt := ast.NewExpressionStatement()
+	return exprStmt
+}
+
+// small_stmt: (expr_stmt | del_stmt | pass_stmt | flow_stmt |
+//              import_stmt | global_stmt | nonlocal_stmt | assert_stmt)
+func (parser *Parser) parseSmallStatment() *ast.SmallStatement {
+	smallStmt := ast.NewSmallStatement()
+
+	var stmt ast.SmallStatementNode
+	stmt = parser.parseExpressionStatement()
+	if stmt != nil {
+		smallStmt.Statement = stmt
+	}
+
+	if stmt == nil {
+		return nil
+	}
+	return smallStmt
+}
+
+// simple_stmt: small_stmt (';' small_stmt)* [';'] NEWLINE
+func (parser *Parser) parseSimpleStatement() *ast.SimpleStatement {
+	simpleStmt := ast.NewSimpleStatement()
+	for {
+		smallStmt := parser.parseSmallStatment()
+		if smallStmt == nil {
+			break
+		}
+		simpleStmt.AppendSmallStatement(smallStmt)
+		next := parser.nextToken()
+		if next.ID != token.SEMI {
+			parser.unreadToken(next)
+			break
+		}
+	}
+	// no small statements found
+	if len(simpleStmt.Statements) == 0 {
+		return nil
+	}
+
+	parser.expect(token.NEWLINE)
+	return simpleStmt
+}
+
+// stmt: simple_stmt | compound_stmt
+func (parser *Parser) parseStatement() *ast.Statement {
+	var next ast.StatementNode
+	next = parser.parseSimpleStatement()
+	if next == nil {
+		next = parser.parseCompoundStatement()
+	}
+
+	if next == nil {
+		return nil
+	}
+
+	stmt := ast.NewStatement()
+	stmt.Statement = next
+	return stmt
+}
+
+// file_input: (NEWLINE | stmt)* ENDMARKER
 func (parser *Parser) parseFileInput() *ast.FileInput {
 	root := ast.NewFileInput()
 	for parser.tokenizer.State() == errorcode.E_OK {
@@ -37,22 +123,30 @@ func (parser *Parser) parseFileInput() *ast.FileInput {
 		if next.ID == token.NEWLINE {
 			root.AppendToken(next)
 		} else if next.ID == token.ENDMARKER {
+			// Unread, so we can read in the expected value later
+			parser.unreadToken(next)
 			break
 		} else {
 			parser.unreadToken(next)
-			// TODO: parser.parseStatement()
+			stmt := parser.parseStatement()
+			if stmt == nil {
+				break
+			}
+			root.AppendNode(stmt)
 			break
 		}
 	}
 
+	parser.expect(token.ENDMARKER)
+
 	return root
 }
 
-func ParseReader(r io.Reader) *ast.FileInput {
+func ParseReader(r io.Reader) (*ast.FileInput, *Parser) {
 	parser := &Parser{
 		tokenizer:   scanner.NewScanner(r),
 		tokenBuffer: make([]*token.Token, 0),
 	}
 
-	return parser.parseFileInput()
+	return parser.parseFileInput(), parser
 }