added print (stdout) and log (logger/stderr) and new -shared-state option for multi file mode, updated readma

Author: ldemailly

README.md

@@ -31,7 +31,9 @@ go install golang.org/x/tools/cmd/stringer@latest
 make # for stripped down executable including build tags etc to make it minimal
 ```
 
-Status: done up to and including 4.5: ie functional int, string and boolean expressions, functions, lambdas, arrays, maps, etc
+Status: All done: ie functional int, string and boolean expressions, functions, lambdas, arrays, maps,
+print, log, and more
+
 
 ### Reading notes
 
@@ -94,3 +96,20 @@ Status: done up to and including 4.5: ie functional int, string and boolean expr
 - [ ] assignment to maps and arrays
 
 - [ ] for loop
+
+### Usage
+
+```
+gorepl 0.15.0 usage:
+	gorepl [flags] *.gr files to interpret or no arg for stdin repl...
+or 1 of the special arguments
+	gorepl {help|envhelp|version|buildinfo}
+flags:
+  -eval
+    	show eval results (default true)
+  -parse
+    	show parse tree
+  -shared-state
+    	All files share same interpreter state (default is new state for each)
+```
+(excluding logger control, see `gorepl help` for all the flags, of note `-logger-no-color` will turn off colors for gorepl too)

apply2.gr

@@ -1,7 +1,7 @@
 // Another example (see sample.gr)
 // Variant with accumulation of result down the stack
 
-a = [ 1, 3, 5, 7]
+a = [ 1, 3, 5, 7] // or run `gorepl -shared-state *.gr` and you can comment this out (a defined in apply.gr)
 
 apply = func(f, a) {
     // helper function

eval/eval.go

@@ -2,6 +2,8 @@ package eval
 
 import (
 	"fmt"
+	"os"
+	"strings"
 
 	"fortio.org/log"
 	"github.com/ldemailly/gorepl/ast"
@@ -43,7 +45,13 @@ func (s *State) evalAssignment(right object.Object, node *ast.InfixExpression) o
 	return right // maybe only if it's a literal?
 }
 
-func ArgCheck[T any](msg string, n int, args []T) *object.Error {
+func ArgCheck[T any](msg string, n int, vararg bool, args []T) *object.Error {
+	if vararg {
+		if len(args) < n {
+			return &object.Error{Value: fmt.Sprintf("%s: wrong number of arguments. got=%d, want at least %d", msg, len(args), n)}
+		}
+		return nil
+	}
 	if len(args) != n {
 		return &object.Error{Value: fmt.Sprintf("%s: wrong number of arguments. got=%d, want=%d", msg, len(args), n)}
 	}
@@ -164,8 +172,9 @@ func (s *State) evalMapLiteral(node *ast.MapLiteral) object.Object {
 }
 
 func (s *State) evalBuiltin(node *ast.Builtin) object.Object {
-	// so far all 3 have exactly 1 argument.
-	if oerr := ArgCheck(node.Literal, 1, node.Parameters); oerr != nil {
+	// all take 1 arg exactly except print and log which take 1+.
+	varArg := node.Type == token.PRINT || node.Type == token.LOG
+	if oerr := ArgCheck(node.Literal, 1, varArg, node.Parameters); oerr != nil {
 		return *oerr
 	}
 	val := s.evalInternal(node.Parameters[0])
@@ -175,6 +184,27 @@ func (s *State) evalBuiltin(node *ast.Builtin) object.Object {
 	}
 	arr, _ := val.(object.Array)
 	switch node.Type { //nolint:exhaustive // we have default, only 2 cases.
+	case token.PRINT:
+		fallthrough
+	case token.LOG:
+		buf := strings.Builder{}
+		for i, v := range node.Parameters {
+			if i > 0 {
+				buf.WriteString(" ")
+			}
+			r := s.evalInternal(v)
+			if isString := r.Type() == object.STRING; isString {
+				buf.WriteString(r.(object.String).Value)
+			} else {
+				buf.WriteString(r.Inspect())
+			}
+		}
+		if node.Type == token.PRINT {
+			os.Stdout.WriteString(buf.String())
+		} else {
+			log.Printf(buf.String())
+		}
+		return object.NULL
 	case token.FIRST:
 		if rt != object.ARRAY {
 			break

main.go

@@ -13,6 +13,7 @@ import (
 func main() {
 	showParse := flag.Bool("parse", false, "show parse tree")
 	showEval := flag.Bool("eval", true, "show eval results")
+	sharedState := flag.Bool("shared-state", false, "All files share same interpreter state (default is new state for each)")
 	cli.ArgsHelp = "*.gr files to interpret or no arg for stdin repl..."
 	cli.MaxArgs = -1
 	cli.Main()
@@ -26,13 +27,18 @@ func main() {
 		return
 	}
 	options.All = true
+	s := eval.NewState()
 	for _, file := range flag.Args() {
-		s := eval.NewState()
 		f, err := os.Open(file)
 		if err != nil {
 			log.Fatalf("%v", err)
 		}
+		log.Infof("Running %s", file)
 		repl.EvalAll(s, f, os.Stdout, options)
 		f.Close()
+		if !*sharedState {
+			s = eval.NewState()
+		}
 	}
+	log.Infof("All done")
 }

parser/parser.go

@@ -76,6 +76,8 @@ func New(l *lexer.Lexer) *Parser {
 	p.registerPrefix(token.LBRACKET, p.parseArrayLiteral)
 	p.registerPrefix(token.LBRACE, p.parseMapLiteral)
 	p.registerPrefix(token.LINECOMMENT, p.parseComment)
+	p.registerPrefix(token.PRINT, p.parseBuiltin)
+	p.registerPrefix(token.LOG, p.parseBuiltin)
 
 	p.infixParseFns = make(map[token.Type]infixParseFn)
 	p.registerInfix(token.PLUS, p.parseInfixExpression)

sample.gr

@@ -3,6 +3,7 @@
 // See also the other *.gr files
 
 fact=func(n) { // function
+    log("called fact ", n) // log (timestamped stderr output)
     if (n<=1) {
         return 1
     }
@@ -13,6 +14,8 @@ a=[fact(5), "abc", 76-3] // array can contain different types
 
 m={"key": a, 73: 29} // so do maps
 
+print("m is:", m, "\n") // stdout print
+
 first(m["key"]) // get the value from key from map, which is an array, and the first element of the array is our factorial 5
 // could also have been m["key"][0]
 

token/token.go

@@ -64,6 +64,8 @@ const (
 	LEN
 	FIRST
 	REST
+	PRINT
+	LOG
 )
 
 //go:generate stringer -type=Type
@@ -81,6 +83,8 @@ var keywords = map[string]Type{
 	"len":   LEN,
 	"first": FIRST,
 	"rest":  REST,
+	"print": PRINT,
+	"log":   LOG,
 }
 
 func LookupIdent(ident string) Type {