String argument version

Author: bhmj

README.md

@@ -31,26 +31,50 @@ Expression examples:
 
 ```Go
     // simple expression evaluation (error handling skipped)
-    result, _ := xpression.Eval([]byte(`5 - 3 * (6-12)`))
+    result, _ := xpression.EvalStr(`5-3*(6-12)`)
     fmt.Println(result.String())
 
     // external data in expression (aka variables)
     foobar := 123
+    varMapper := map[string]*int{
+        `foobar`: &foobar,
+    }
     varFunc := func(name []byte, result *xpression.Operand) error {
-        mapper := map[string]*int{
-            `foobar`: &foobar,
-        }
-        ref := mapper[string(name)]
+        ref := varMapper[string(name)]
         if ref == nil {
             return errors.New("unknown variable")
         }
         result.SetNumber(float64(*ref))
         return nil
     }
-    result, _ = xpression.EvalVar([]byte(`27 / foobar`), varFunc)
+    result, _ = xpression.EvalVarStr(`27 / foobar`, varFunc)
     fmt.Println(result.String())
 ```
-[Run in Go Playground](https://play.golang.com/p/5gqKN1DkCXp)
+[Run in Go Playground](https://play.golang.com/p/YaweDHqUJKa)
+
+## Functions
+
+```Go
+func Eval(expression []byte) (*Operand, error)
+```
+Eval evaluates expression and returns the result. No external variables used. See EvalVar for more.
+Returns a pointer to Operand or error.
+Use Operand's method `.String()` to get a serializable value or see Operand's `.OperandType` field to determine the result type and get the value from `.Str`, `.Number` or `.Bool` field.
+
+```Go
+func EvalVar(expression []byte, varFunc VariableFunc) (*Operand, error)
+```
+`EvalVar` evaluates expression and returns the result. External variables can be used via `varFunc`.
+
+```Go
+func EvalStr(expression string) (*Operand, error)
+```
+Same as `Eval` but receives a `string` instean of `[]byte`.
+
+```Go
+func EvalVarStr(expression string, varFunc VariableFunc) (*Operand, error)
+```
+Same as `EvalVar` but receives a `string` instean of `[]byte`.
 
 ## xpression CLI
 
@@ -123,6 +147,7 @@ ok      github.com/Knetic/govaluate     9.810s
 
 ## Changelog
 
+**0.9.4** (2022-11-28) -- Go 1.19 support. `EvalStr` and `EvalVarStr` helper functions added.  
 **0.9.3** (2022-07-06) -- bugfixes: string to hex conversion `"0x123"*2`, closing bracket after a variable `(0+a)`.  
 **0.9.2** (2022-02-23) -- Minor code refactoring. One-liner functions added (Eval, EvalVar).  
 **0.9.1** (2022-01-02) -- Variable bounds refined.  

eval.go

@@ -9,6 +9,11 @@ func Eval(expression []byte) (*Operand, error) {
 	return Evaluate(tokens, nil)
 }
 
+// EvalStr is a wrapper for string expression.
+func EvalStr(expression string) (*Operand, error) {
+	return Eval([]byte(expression))
+}
+
 // EvalVar evaluates expression and returns the result. External variables can be used via varFunc.
 func EvalVar(expression []byte, varFunc VariableFunc) (*Operand, error) {
 	tokens, err := Parse(expression)
@@ -17,3 +22,8 @@ func EvalVar(expression []byte, varFunc VariableFunc) (*Operand, error) {
 	}
 	return Evaluate(tokens, varFunc)
 }
+
+// EvalStrVar evaluates expression and returns the result. External variables can be used via varFunc.
+func EvalVarStr(expression string, varFunc VariableFunc) (*Operand, error) {
+	return EvalVar([]byte(expression), varFunc)
+}

go.mod

@@ -1,10 +1,10 @@
 module github.com/bhmj/xpression
 
-go 1.17
+go 1.19
 
-require github.com/bhmj/readline v0.0.0-20220705162457-b109d6dec1af
+require github.com/bhmj/readline v0.1.0
 
 require (
 	github.com/pkg/term v1.1.0 // indirect
-	golang.org/x/sys v0.0.0-20200909081042-eff7692f9009 // indirect
+	golang.org/x/sys v0.2.0 // indirect
 )

go.sum

@@ -1,6 +1,7 @@
-github.com/bhmj/readline v0.0.0-20220705162457-b109d6dec1af h1:qPvq5oXPg0lhWxqH8CyRqGMR8PhuTYZdTmbmRiWLePI=
-github.com/bhmj/readline v0.0.0-20220705162457-b109d6dec1af/go.mod h1:mT/+5iXLVS567ObbD2EUub7BS1hnb+o8Sz2CmVNJFf4=
+github.com/bhmj/readline v0.1.0 h1:j42+cSkBUlAhLVuF/zzuD6Bjvej0k7eA4vzb53lMGew=
+github.com/bhmj/readline v0.1.0/go.mod h1:mT/+5iXLVS567ObbD2EUub7BS1hnb+o8Sz2CmVNJFf4=
 github.com/pkg/term v1.1.0 h1:xIAAdCMh3QIAy+5FrE8Ad8XoDhEU4ufwbaSozViP9kk=
 github.com/pkg/term v1.1.0/go.mod h1:E25nymQcrSllhX42Ok8MRm1+hyBdHY0dCeiKZ9jpNGw=
-golang.org/x/sys v0.0.0-20200909081042-eff7692f9009 h1:W0lCpv29Hv0UaM1LXb9QlBHLNP8UFfcKjblhVCWftOM=
 golang.org/x/sys v0.0.0-20200909081042-eff7692f9009/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.2.0 h1:ljd4t30dBnAvMZaQCevtY0xLLD0A+bRZXbgLMLU1F/A=
+golang.org/x/sys v0.2.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=