Golang NewMacro Examples

Example #1

File: macros.go Project: raoulvdberge/risp

func builtinDefmacro(context *runtime.MacroCallContext) (*runtime.Value, error) {
	name := context.Nodes[0].(*parser.IdentifierNode).Token.Data

	if name == "_" {
		return nil, runtime.NewRuntimeError(context.Nodes[0].Pos(), "disallowed macro name")
	}

	if context.Block.Scope.GetSymbol(name) != nil && context.Block.Scope.GetSymbol(name).Const {
		return nil, runtime.NewRuntimeError(context.Nodes[0].Pos(), "%s is a constant and cannot be modified", name)
	}

	argNodes := context.Nodes[1].(*parser.ListNode)
	var args []string
	callback := context.Nodes[2].(*parser.ListNode)

	if len(callback.Nodes) == 0 {
		return nil, runtime.NewRuntimeError(callback.Pos(), "empty macro body")
	}

	for _, argNode := range argNodes.Nodes {
		ident, ok := argNode.(*parser.IdentifierNode)

		if !ok {
			return nil, runtime.NewRuntimeError(argNode.Pos(), "expected an identifier")
		}

		args = append(args, ident.Token.Data)
	}

	macro := runtime.NewMacro(func(handlerContext *runtime.MacroCallContext) (*runtime.Value, error) {
		block := runtime.NewBlock([]parser.Node{callback}, runtime.NewScope(handlerContext.Block.Scope))

		for i, arg := range args {
			block.Scope.SetSymbolLocally(arg, runtime.NewSymbol(runtime.NewQuotedValue(handlerContext.Nodes[i])))
		}

		return block.Eval()
	}, false)

	context.Block.Scope.SetMacro(name, macro)

	return runtime.Nil, nil
}

Example #2

File: macros.go Project: raoulvdberge/risp

package builtin

import (
	"github.com/raoulvdberge/risp/parser"
	"github.com/raoulvdberge/risp/runtime"
)

var Macros = runtime.Mactab{
	"defun":     runtime.NewMacro(builtinDefun, true, "identifier", "list", "list"),
	"def":       runtime.NewMacro(builtinDef, true, "identifier", "any"),
	"defmacro":  runtime.NewMacro(builtinDefmacro, true, "identifier", "list", "list"),
	"defconst":  runtime.NewMacro(builtinDef, true, "identifier", "any"),
	"fun":       runtime.NewMacro(builtinFun, true, "list", "list"),
	"for":       runtime.NewMacro(builtinFor, true, "any", "list", "list"),
	"while":     runtime.NewMacro(builtinWhile, true, "any", "list"),
	"if":        runtime.NewMacro(builtinIf, true, "any", "any"),
	"ifel":      runtime.NewMacro(builtinIfel, true, "any", "any", "any"),
	"case":      runtime.NewMacro(builtinCase, false),
	"export":    runtime.NewMacro(builtinExport, false),
	"namespace": runtime.NewMacro(builtinNamespace, true, "identifier"),
}

func builtinDefmacro(context *runtime.MacroCallContext) (*runtime.Value, error) {
	name := context.Nodes[0].(*parser.IdentifierNode).Token.Data

	if name == "_" {
		return nil, runtime.NewRuntimeError(context.Nodes[0].Pos(), "disallowed macro name")
	}

	if context.Block.Scope.GetSymbol(name) != nil && context.Block.Scope.GetSymbol(name).Const {
		return nil, runtime.NewRuntimeError(context.Nodes[0].Pos(), "%s is a constant and cannot be modified", name)

Example #3

File: macros.go Project: raoulvdberge/risp

package list

import (
	"github.com/raoulvdberge/risp/parser"
	"github.com/raoulvdberge/risp/runtime"
)

var Macros = runtime.Mactab{
	"filter": runtime.NewMacro(listFilter, true, "any", "identifier", "list"),
	"map":    runtime.NewMacro(listMap, true, "any", "identifier", "list"),
	"reduce": runtime.NewMacro(listReduce, true, "any", "identifier", "identifier", "list"),
}

func listFilter(context *runtime.MacroCallContext) (*runtime.Value, error) {
	list, err := context.Block.EvalNode(context.Nodes[0])

	if err != nil {
		return nil, err
	}

	if list.Type != runtime.ListValue {
		return nil, runtime.NewRuntimeError(context.Nodes[0].Pos(), "expected a list")
	}

	ident := context.Nodes[1].(*parser.IdentifierNode).Token.Data

	callback := context.Nodes[2]

	filteredList := runtime.NewListValue()

	for _, item := range list.List {