diff --git a/docs/client.md b/docs/client.md
index d8d9805..9cd5b96 100644
--- a/docs/client.md
+++ b/docs/client.md
@@ -32,7 +32,7 @@ Setting the locales can be done with `i18nClient.setLocales([...])`.
 
 ### Other locales
 
-The `I18nClient` also have 2 properties:
+The `I18nClient` also has 2 properties:
 
 - `timeZone`: A timezone used when displaying dates (if none is specified) with [this format](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Intl/DateTimeFormat)
 - `currency`: A currency to use when displaying a number with `style: currency` (3-uppercase code: USD, EUR, ...)
diff --git a/docs/interpolation.md b/docs/interpolation.md
index ed7eb28..8b74e5c 100644
--- a/docs/interpolation.md
+++ b/docs/interpolation.md
@@ -78,11 +78,11 @@ Object.assign(processors, {
 Where `TContext` contains mostly the `client` (the object containing all the language specification)
 The arguments will mainly be strings or object when flat named lists are specified
 
-The syntax to use them is `{processor | arg1 | arg2}`.
+The syntax to use them is `{processor:: arg1 | arg2}`.
 
-example: `{upper | $1}` will render the first argument in upper-case
+example: `{upper :: $1}` will render the first argument in upper-case
 
-> :information_source: `{$2[upper] | $1}` is also possible, in which case the second argument can both specify a text key, a processor or be defaulted to the `upper` processor.
+> :information_source: `{$2[upper] :: $1}` is also possible, in which case the second argument can both specify a text key, a processor or be defaulted to the `upper` processor.
 
 #### Casing
 
diff --git a/src/client/interpolation.ts b/src/client/interpolation.ts
index d52cbcf..b1559c7 100644
--- a/src/client/interpolation.ts
+++ b/src/client/interpolation.ts
@@ -30,6 +30,7 @@ export const formats: Record<'date' | 'number' | 'relative', Record<string, obje
 }
 
 export const processors: Record<string, (...args: any[]) => string> = {
+	// TODO Interpolation should have access to localeFlagsEngine
 	upper(str: string) {
 		return str.toUpperCase()
 	},