Syntax Errors

.gitignore

@@ -22,4 +22,4 @@ go.work
 
 # Go binaries
 solgo
-examples/examples
+prototype/*

data/tests/BuggyContract.sol

@@ -0,0 +1,25 @@
+pragma solidity ^0.8.0;
+
+contract TestContract {
+    uint256 public count;
+
+    // Missing semicolon
+    function increment() public {
+        count += 1
+    }
+
+    // Mismatched parentheses
+    function decrement() public {
+        count -= 1;
+    }
+
+    // Missing function keyword
+    setCount(uint256 _count) public {
+        count = _count;
+    }
+
+    // Extraneous input 'returns'
+    function getCount() public returns (uint256) {
+        return count
+    }
+}

listeners.go

@@ -14,8 +14,13 @@ const (
 	ListenerAbi          ListenerName = "abi"
 	ListenerContractInfo ListenerName = "contract_info"
 	ListenerAst          ListenerName = "ast"
+	ListenerSyntaxErrors ListenerName = "syntax_errors"
 )
 
+func (l ListenerName) String() string {
+	return string(l)
+}
+
 type listeners map[ListenerName]antlr.ParseTreeListener
 
 func (s *SolGo) RegisterListener(name ListenerName, listener antlr.ParseTreeListener) error {

solgo.go

@@ -7,6 +7,8 @@ import (
 
 	"github.com/antlr4-go/antlr/v4"
 	"github.com/txpull/solgo/parser"
+	"github.com/txpull/solgo/syntaxerrors"
+	"go.uber.org/zap"
 )
 
 // SolGo is a struct that encapsulates the functionality for parsing and analyzing Solidity contracts.
@@ -22,12 +24,12 @@ type SolGo struct {
 	// tokenStream is the stream of tokens produced by the lexer.
 	tokenStream *antlr.CommonTokenStream
 	// solidityParser is the Solidity parser which parses the token stream.
-	solidityParser *parser.SolidityParser
+	solidityParser *syntaxerrors.ContextualParser
 	// listeners is a map of listener names to ParseTreeListener instances.
 	// These listeners are invoked as the parser walks the parse tree.
 	listeners listeners
 	// errListener is a SyntaxErrorListener which collects syntax errors encountered during parsing.
-	errListener *SyntaxErrorListener
+	errListener *syntaxerrors.SyntaxErrorListener
 }
 
 // New creates a new instance of SolGo.
@@ -43,7 +45,7 @@ func New(ctx context.Context, input io.Reader) (*SolGo, error) {
 	inputStream := antlr.NewInputStream(string(ib))
 
 	// Create a new SyntaxErrorListener
-	errListener := NewSyntaxErrorListener()
+	errListener := syntaxerrors.NewSyntaxErrorListener()
 
 	// Create a new Solidity lexer with the input stream
 	lexer := parser.NewSolidityLexer(inputStream)
@@ -57,22 +59,16 @@ func New(ctx context.Context, input io.Reader) (*SolGo, error) {
 	// Create a new token stream from the lexer
 	stream := antlr.NewCommonTokenStream(lexer, antlr.TokenDefaultChannel)
 
-	// Create a new Solidity parser with the token stream
-	solidityParser := parser.NewSolidityParser(stream)
-
-	// Remove the default error listeners
-	solidityParser.RemoveErrorListeners()
-
-	// Add our SyntaxErrorListener
-	solidityParser.AddErrorListener(errListener)
+	// Create a new ContextualParser with the token stream and listener
+	contextualParser := syntaxerrors.NewContextualParser(stream, errListener)
 
 	return &SolGo{
 		ctx:            ctx,
 		inputRaw:       input,
 		inputStream:    inputStream,
 		lexer:          lexer,
 		tokenStream:    stream,
-		solidityParser: solidityParser,
+		solidityParser: contextualParser,
 		errListener:    errListener,
 		listeners:      make(listeners),
 	}, nil
@@ -100,6 +96,11 @@ func (s *SolGo) GetTokenStream() *antlr.CommonTokenStream {
 
 // GetParser returns the Solidity parser which parses the token stream.
 func (s *SolGo) GetParser() *parser.SolidityParser {
+	return s.solidityParser.SolidityParser
+}
+
+// GetContextualParser returns the ContextualParser which wraps the Solidity parser.
+func (s *SolGo) GetContextualParser() *syntaxerrors.ContextualParser {
 	return s.solidityParser
 }
 
@@ -110,11 +111,15 @@ func (s *SolGo) GetTree() antlr.ParseTree {
 
 // Parse initiates the parsing process. It walks the parse tree with all registered listeners
 // and returns any syntax errors that were encountered during parsing.
-func (s *SolGo) Parse() []SyntaxError {
+func (s *SolGo) Parse() []syntaxerrors.SyntaxError {
 	tree := s.GetTree()
 
 	// Walk the parse tree with all registered listeners
-	for _, listener := range s.GetAllListeners() {
+	for name, listener := range s.GetAllListeners() {
+		zap.L().Debug(
+			"walking parse tree",
+			zap.String("listener", name.String()),
+		)
 		antlr.ParseTreeWalkerDefault.Walk(listener, tree)
 	}
 

solgo_test.go

@@ -6,6 +6,8 @@ import (
 	"testing"
 
 	"github.com/stretchr/testify/assert"
+	"github.com/txpull/solgo/syntaxerrors"
+	"github.com/txpull/solgo/tests"
 )
 
 func TestNew(t *testing.T) {
@@ -94,3 +96,74 @@ func TestGetInput(t *testing.T) {
 
 	assert.Equal(t, input, solgo.GetInput(), "input reader is not returned correctly")
 }
+
+func TestNew_SyntaxErrors(t *testing.T) {
+	testCases := []struct {
+		name     string
+		contract string
+		expected []syntaxerrors.SyntaxError
+	}{
+		{
+			name:     "Randomly Corrupted Contract",
+			contract: tests.ReadContractFileForTestFromRootPath(t, "BuggyContract").Content,
+			expected: []syntaxerrors.SyntaxError{
+				{
+					Line:     9,
+					Column:   4,
+					Message:  "missing ';' at '}'",
+					Severity: syntaxerrors.SeverityError,
+					Context:  "SourceUnit",
+				},
+				{
+					Line:     17,
+					Column:   12,
+					Message:  "mismatched input '(' expecting {'constant', 'error', 'from', 'global', 'immutable', 'internal', 'override', 'private', 'public', 'revert', Identifier}",
+					Severity: syntaxerrors.SeverityError,
+					Context:  "SourceUnit",
+				},
+				{
+					Line:     17,
+					Column:   27,
+					Message:  "mismatched input ')' expecting {';', '='}",
+					Severity: syntaxerrors.SeverityError,
+					Context:  "SourceUnit",
+				},
+				{
+					Line:     18,
+					Column:   14,
+					Message:  "extraneous input '=' expecting {'constant', 'error', 'from', 'global', 'immutable', 'internal', 'override', 'private', 'public', 'revert', Identifier}",
+					Severity: syntaxerrors.SeverityError,
+					Context:  "SourceUnit",
+				},
+				{
+					Line:     24,
+					Column:   4,
+					Message:  "missing ';' at '}'",
+					Severity: syntaxerrors.SeverityError,
+					Context:  "SourceUnit",
+				},
+				{
+					Line:     25,
+					Column:   0,
+					Message:  "extraneous input '}' expecting {<EOF>, 'abstract', 'address', 'bool', 'bytes', 'contract', 'enum', 'error', Fixed, FixedBytes, 'from', Function, 'global', 'import', 'interface', 'library', 'mapping', 'pragma', 'revert', SignedIntegerType, 'string', 'struct', 'type', Ufixed, UnsignedIntegerType, 'using', Identifier}",
+					Severity: syntaxerrors.SeverityError,
+					Context:  "SourceUnit",
+				},
+			},
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			// Create a new SolGo instance
+			solGo, err := New(context.Background(), strings.NewReader(tc.contract))
+			assert.NoError(t, err)
+			assert.NotNil(t, solGo)
+
+			syntaxErrors := solGo.Parse()
+
+			// Check that the syntax errors match the expected syntax errors
+			assert.Equal(t, tc.expected, syntaxErrors)
+		})
+	}
+}