Allow converting to numbers

Author: imbstack

jsone.go

@@ -177,6 +177,9 @@ var builtin = map[string]interface{}{
 			return "", fmt.Errorf("str(value) only works on strings, numbers, booleans and null")
 		}
 	}),
+	"number": i.WrapFunction(func(s string) (float64, error) {
+		return strconv.ParseFloat(s, 64)
+	}),
 	"typeof": i.WrapFunction(func(v interface{}) interface{} {
 		switch v.(type) {
 		case string:

jsone/builtins.py

@@ -83,6 +83,7 @@ def lowercase(v):
 
     builtin('len', argument_tests=[is_string_or_array])(len)
     builtin('str', argument_tests=[anything_except_array])(to_str)
+    builtin('number', variadic=is_string, minArgs=1)(float)
 
     @builtin('strip', argument_tests=[is_string])
     def strip(s):

jsone/newsfragments/240.feature

@@ -0,0 +1 @@
+Add a `number` builtin that converts strings to numbers

specification.yml

@@ -1666,6 +1666,31 @@ context: {key: [1, 2, 3]}
 template: {$eval: 'str(key)'}
 error: 'BuiltinError: invalid arguments to builtin: str'
 ---
+title:    number
+context:  {round: "3"}
+template: {foo: {$eval: number(round)}}
+result:   {foo: 3}
+---
+title:    number (with point)
+context:  {round: "3.5"}
+template: {foo: {$eval: number(round)}}
+result:   {foo: 3.5}
+---
+title:    negative number
+context:  {round: "-14"}
+template: {foo: {$eval: number(round)}}
+result:   {foo: -14}
+---
+title:    negative number (with point)
+context:  {round: "-14.15"}
+template: {foo: {$eval: number(round)}}
+result:   {foo: -14.15}
+---
+title:    number zero
+context:  {round: "0"}
+template: {foo: {$eval: number(round)}}
+result:   {foo: 0}
+---
 title: strip space
 context: {}
 template: {$eval: "strip('  abc   ')"}

src/builtins.js

@@ -91,6 +91,11 @@ module.exports = (context) => {
     },
   });
 
+  define('number', builtins, {
+    argumentTests: ['string'],
+    invoke: Number,
+  });
+
   define('len', builtins, {
     argumentTests: ['string|array'],
     invoke: obj => Array.from(obj).length,