Improved code layout

src/build/scan.go

@@ -0,0 +1,234 @@
+package build
+
+import (
+	"os"
+	"path/filepath"
+	"strings"
+	"sync"
+
+	"git.akyoto.dev/cli/q/src/build/fs"
+	"git.akyoto.dev/cli/q/src/build/token"
+	"git.akyoto.dev/cli/q/src/errors"
+)
+
+// scan scans the directory.
+func scan(files []string) (<-chan *Function, <-chan error) {
+	functions := make(chan *Function)
+	errors := make(chan error)
+
+	go func() {
+		scanFiles(files, functions, errors)
+		close(functions)
+		close(errors)
+	}()
+
+	return functions, errors
+}
+
+// scanFiles scans the list of files without channel allocations.
+func scanFiles(files []string, functions chan<- *Function, errors chan<- error) {
+	wg := sync.WaitGroup{}
+
+	for _, file := range files {
+		stat, err := os.Stat(file)
+
+		if err != nil {
+			errors <- err
+			return
+		}
+
+		if stat.IsDir() {
+			err = fs.Walk(file, func(name string) {
+				if !strings.HasSuffix(name, ".q") {
+					return
+				}
+
+				fullPath := filepath.Join(file, name)
+				wg.Add(1)
+
+				go func() {
+					defer wg.Done()
+					err := scanFile(fullPath, functions)
+
+					if err != nil {
+						errors <- err
+					}
+				}()
+			})
+
+			if err != nil {
+				errors <- err
+			}
+		} else {
+			wg.Add(1)
+
+			go func() {
+				defer wg.Done()
+				err := scanFile(file, functions)
+
+				if err != nil {
+					errors <- err
+				}
+			}()
+		}
+	}
+
+	wg.Wait()
+}
+
+// scanFile scans a single file.
+func scanFile(path string, functions chan<- *Function) error {
+	contents, err := os.ReadFile(path)
+
+	if err != nil {
+		return err
+	}
+
+	tokens := token.Tokenize(contents)
+
+	file := &fs.File{
+		Tokens: tokens,
+		Path:   path,
+	}
+
+	var (
+		i           = 0
+		groupLevel  = 0
+		blockLevel  = 0
+		nameStart   = -1
+		paramsStart = -1
+		bodyStart   = -1
+	)
+
+	for {
+		// Function name
+		for i < len(tokens) {
+			if tokens[i].Kind == token.Identifier {
+				nameStart = i
+				i++
+				break
+			}
+
+			if tokens[i].Kind == token.NewLine {
+				i++
+				continue
+			}
+
+			if tokens[i].Kind == token.EOF {
+				return nil
+			}
+
+			return errors.New(errors.ExpectedFunctionName, file, tokens[i].Position)
+		}
+
+		// Function parameters
+		for i < len(tokens) {
+			if tokens[i].Kind == token.GroupStart {
+				groupLevel++
+
+				if groupLevel == 1 {
+					paramsStart = i
+				}
+
+				i++
+				continue
+			}
+
+			if tokens[i].Kind == token.GroupEnd {
+				groupLevel--
+
+				if groupLevel < 0 {
+					return errors.New(errors.MissingGroupStart, file, tokens[i].Position)
+				}
+
+				i++
+
+				if groupLevel == 0 {
+					break
+				}
+
+				continue
+			}
+
+			if tokens[i].Kind == token.EOF {
+				if groupLevel > 0 {
+					return errors.New(errors.MissingGroupEnd, file, tokens[i].Position)
+				}
+
+				if paramsStart == -1 {
+					return errors.New(errors.ExpectedFunctionParameters, file, tokens[i].Position)
+				}
+
+				return nil
+			}
+
+			if groupLevel > 0 {
+				i++
+				continue
+			}
+
+			return errors.New(errors.ExpectedFunctionParameters, file, tokens[i].Position)
+		}
+
+		// Function definition
+		for i < len(tokens) {
+			if tokens[i].Kind == token.BlockStart {
+				blockLevel++
+
+				if blockLevel == 1 {
+					bodyStart = i
+				}
+
+				i++
+				continue
+			}
+
+			if tokens[i].Kind == token.BlockEnd {
+				blockLevel--
+
+				if blockLevel < 0 {
+					return errors.New(errors.MissingBlockStart, file, tokens[i].Position)
+				}
+
+				i++
+
+				if blockLevel == 0 {
+					break
+				}
+
+				continue
+			}
+
+			if tokens[i].Kind == token.EOF {
+				if blockLevel > 0 {
+					return errors.New(errors.MissingBlockEnd, file, tokens[i].Position)
+				}
+
+				if bodyStart == -1 {
+					return errors.New(errors.ExpectedFunctionDefinition, file, tokens[i].Position)
+				}
+
+				return nil
+			}
+
+			if blockLevel > 0 {
+				i++
+				continue
+			}
+
+			return errors.New(errors.ExpectedFunctionDefinition, file, tokens[i].Position)
+		}
+
+		functions <- &Function{
+			Name:      tokens[nameStart].Text(),
+			File:      file,
+			Head:      tokens[paramsStart:bodyStart],
+			Body:      tokens[bodyStart : i+1],
+			Variables: map[string]*Variable{},
+		}
+
+		nameStart = -1
+		paramsStart = -1
+		bodyStart = -1
+	}
+}