Hello world

pkg/compiler/compiler.go

@@ -0,0 +1,68 @@
+package compiler
+
+import (
+	"github.com/MontFerret/ferret/pkg/parser"
+	"github.com/MontFerret/ferret/pkg/runtime"
+	"github.com/MontFerret/ferret/pkg/runtime/core"
+	"github.com/MontFerret/ferret/pkg/stdlib"
+	"github.com/pkg/errors"
+)
+
+type FqlCompiler struct {
+	funcs map[string]core.Function
+}
+
+func New() *FqlCompiler {
+	return &FqlCompiler{
+		stdlib.NewLib(),
+	}
+}
+
+func (c *FqlCompiler) RegisterFunction(name string, fun core.Function) error {
+	_, exists := c.funcs[name]
+
+	if exists {
+		return errors.Errorf("function already exists: %s", name)
+	}
+
+	c.funcs[name] = fun
+
+	return nil
+}
+
+func (c *FqlCompiler) Compile(query string) (program *runtime.Program, err error) {
+	if query == "" {
+		return nil, ErrEmptyQuery
+	}
+
+	p := parser.New(query)
+	p.AddErrorListener(&errorListener{})
+
+	defer func() {
+		if r := recover(); r != nil {
+			// find out exactly what the error was and set err
+			switch x := r.(type) {
+			case string:
+				err = errors.New(x)
+			case error:
+				err = x
+			default:
+				err = errors.New("unknown panic")
+			}
+
+			program = nil
+		}
+	}()
+
+	l := newVisitor(c.funcs)
+
+	res := p.Visit(l).(*result)
+
+	if res.Ok() {
+		program = res.Data().(*runtime.Program)
+	} else {
+		err = res.Error()
+	}
+
+	return program, err
+}