[IMP] translation contexts

A new directive t-tanslation-context and a new family of directives (of the form
t-translation-context-...) are introduced to allow to translate terms in contexts.

Set t-translation-context="fr" on a node makes every call of the translation
function to be done with "fr" as seconde parameter when translating an
attribute/content within that node or its children (if no closer
t-translation-context directive is found).
A directive t-translation-context-attr="fr" can be used on a node to target its
attribute "attr". For example, if a div has an attribute title="a title",
use t-translation-context-title="pt" will make "a title" to be translated
in the context "pt". Note that this takes precedence over any other directive
t-translation-context found on a parent (or the div itself).
The translation function is in charge of the interpretation of the context: OWL
does not associates any meaning with a translation context.

doc/reference/templates.md

@@ -56,17 +56,19 @@ extensions.
 
 For reference, here is a list of all standard QWeb directives:
 
-| Name                           | Description                                                     |
-| ------------------------------ | --------------------------------------------------------------- |
-| `t-esc`                        | [Outputting safely a value](#outputting-data)                   |
-| `t-out`                        | [Outputting value, possibly without escaping](#outputting-data) |
-| `t-set`, `t-value`             | [Setting variables](#setting-variables)                         |
-| `t-if`, `t-elif`, `t-else`,    | [conditionally rendering](#conditionals)                        |
-| `t-foreach`, `t-as`            | [Loops](#loops)                                                 |
-| `t-att`, `t-attf-*`, `t-att-*` | [Dynamic attributes](#dynamic-attributes)                       |
-| `t-call`                       | [Rendering sub templates](#sub-templates)                       |
-| `t-debug`, `t-log`             | [Debugging](#debugging)                                         |
-| `t-translation`                | [Disabling the translation of a node](translations.md)          |
+| Name                           | Description                                                          |
+| ------------------------------ | -------------------------------------------------------------------- |
+| `t-esc`                        | [Outputting safely a value](#outputting-data)                        |
+| `t-out`                        | [Outputting value, possibly without escaping](#outputting-data)      |
+| `t-set`, `t-value`             | [Setting variables](#setting-variables)                              |
+| `t-if`, `t-elif`, `t-else`,    | [conditionally rendering](#conditionals)                             |
+| `t-foreach`, `t-as`            | [Loops](#loops)                                                      |
+| `t-att`, `t-attf-*`, `t-att-*` | [Dynamic attributes](#dynamic-attributes)                            |
+| `t-call`                       | [Rendering sub templates](#sub-templates)                            |
+| `t-debug`, `t-log`             | [Debugging](#debugging)                                              |
+| `t-translation`                | [Disabling the translation of a node](translations.md)               |
+| `t-translation-context`        | [Context of translations within a node](translations.md)             |
+| `t-translation-context-*`      | [Context of translation for the attribute targeted](translations.md) |
 
 The component system in Owl requires additional directives, to express various
 needs. Here is a list of all Owl specific directives:

doc/reference/translations.md

@@ -1,7 +1,8 @@
 # 🦉 Translations 🦉
 
 If properly setup, Owl can translate all rendered templates. To do
-so, it needs a translate function, which takes a string and returns a string.
+so, it needs a translate function, which takes a string (and an optional string)
+and returns a string.
 
 For example:
 
@@ -11,7 +12,7 @@ const translations = {
   yes: "oui",
   no: "non",
 };
-const translateFn = (str) => translations[str] || str;
+const translateFn = (str, ctx) => translations[str] || str;
 
 const app = new App(Root, { templates, tranaslateFn });
 // ...
@@ -27,6 +28,11 @@ Once setup, all rendered templates will be translated using `translateFn`:
   `placeholder`, `label` and `alt`,
 - translating text nodes can be disabled with the special attribute `t-translation`,
   if its value is `off`.
+- the translate function receives as second parameter a context (a string or
+  null) that can be used to contextualized the translation. That context can be
+  set globally on a node and its children by using `t-translation-context`. If
+  a specific node attribute `x` needs another context, that context can be
+  specified with a special directive `t-translation-context-x`.
 
 So, with the above `translateFn`, the following templates:
 
@@ -46,6 +52,22 @@ will be rendered as:
 <input placeholder="bonjour" other="yes"/>
 ```
 
+and the following template:
+
+```xml
+<div t-translation-context="fr" title="hello">hello</div>
+<div>Are you sure?</div>
+<input t-translation-placeholder="pt" placeholder="hello" other="yes"/>
+```
+
+will be rendered as:
+
+```xml
+<div title="bonjour">bonjour</div>
+<div>Are you sure?</div>
+<input placeholder="bom dia" other="yes"/>
+```
+
 Note that the translation is done during the compilation of the template, not
 when it is rendered.
 

src/compiler/code_generator.ts

@@ -24,6 +24,7 @@ import {
   ASTTOut,
   ASTTPortal,
   ASTTranslation,
+  ASTTranslationContext,
   ASTTSet,
   ASTType,
   Attrs,
@@ -35,7 +36,7 @@ type BlockType = "block" | "text" | "multi" | "list" | "html" | "comment";
 const whitespaceRE = /\s+/g;
 
 export interface Config {
-  translateFn?: (s: string) => string;
+  translateFn?: (s: string, translationCtx: string | null) => string;
   translatableAttributes?: string[];
   dev?: boolean;
 }
@@ -171,6 +172,7 @@ interface Context {
   forceNewBlock: boolean;
   isLast?: boolean;
   translate: boolean;
+  translationCtx: string | null;
   tKeyExpr: string | null;
   nameSpace?: string;
   tModelSelectedExpr?: string;
@@ -185,6 +187,7 @@ function createContext(parentCtx: Context, params?: Partial<Context>): Context {
       index: 0,
       forceNewBlock: true,
       translate: parentCtx.translate,
+      translationCtx: parentCtx.translationCtx,
       tKeyExpr: null,
       nameSpace: parentCtx.nameSpace,
       tModelSelectedExpr: parentCtx.tModelSelectedExpr,
@@ -263,7 +266,7 @@ export class CodeGenerator {
   target = new CodeTarget("template");
   templateName?: string;
   dev: boolean;
-  translateFn: (s: string) => string;
+  translateFn: (s: string, translationCtx: string | null) => string;
   translatableAttributes: string[] = TRANSLATABLE_ATTRS;
   ast: AST;
   staticDefs: { id: string; expr: string }[] = [];
@@ -303,6 +306,7 @@ export class CodeGenerator {
       forceNewBlock: false,
       isLast: true,
       translate: true,
+      translationCtx: null,
       tKeyExpr: null,
     });
     // define blocks and utility functions
@@ -457,9 +461,9 @@ export class CodeGenerator {
       .join("");
   }
 
-  translate(str: string): string {
+  translate(str: string, translationCtx: string | null): string {
     const match = translationRE.exec(str) as any;
-    return match[1] + this.translateFn(match[2]) + match[3];
+    return match[1] + this.translateFn(match[2], translationCtx) + match[3];
   }
 
   /**
@@ -501,6 +505,8 @@ export class CodeGenerator {
         return this.compileTSlot(ast, ctx);
       case ASTType.TTranslation:
         return this.compileTTranslation(ast, ctx);
+      case ASTType.TTranslationContext:
+        return this.compileTTranslationContext(ast, ctx);
       case ASTType.TPortal:
         return this.compileTPortal(ast, ctx);
     }
@@ -542,7 +548,7 @@ export class CodeGenerator {
 
     let value = ast.value;
     if (value && ctx.translate !== false) {
-      value = this.translate(value);
+      value = this.translate(value, ctx.translationCtx);
     }
     if (!ctx.inPreTag) {
       value = value.replace(whitespaceRE, " ");
@@ -631,7 +637,8 @@ export class CodeGenerator {
           }
         }
       } else if (this.translatableAttributes.includes(key)) {
-        attrs[key] = this.translateFn(ast.attrs[key]);
+        const attrTranslationCtx = ast.attrsTranslationCtx?.[key] || ctx.translationCtx;
+        attrs[key] = this.translateFn(ast.attrs[key], attrTranslationCtx);
       } else {
         expr = `"${ast.attrs[key]}"`;
         attrName = key;
@@ -1104,7 +1111,7 @@ export class CodeGenerator {
       let value: string;
       if (ast.defaultValue) {
         const defaultValue = toStringExpression(
-          ctx.translate ? this.translate(ast.defaultValue) : ast.defaultValue
+          ctx.translate ? this.translate(ast.defaultValue, ctx.translationCtx) : ast.defaultValue
         );
         if (ast.value) {
           value = `withDefault(${expr}, ${defaultValue})`;
@@ -1139,9 +1146,15 @@ export class CodeGenerator {
    * "some-prop"       "state"          "'some-prop': ctx['state']"
    * "onClick.bind"    "onClick"        "onClick: bind(ctx, ctx['onClick'])"
    */
-  formatProp(name: string, value: string): string {
+  formatProp(
+    name: string,
+    value: string,
+    attrsTranslationCtx: { [name: string]: string } | null,
+    translationCtx: string | null
+  ): string {
     if (name.endsWith(".translate")) {
-      value = toStringExpression(this.translateFn(value));
+      const attrTranslationCtx = attrsTranslationCtx?.[name] || translationCtx;
+      value = toStringExpression(this.translateFn(value, attrTranslationCtx));
     } else {
       value = this.captureExpression(value);
     }
@@ -1163,8 +1176,14 @@ export class CodeGenerator {
     return `${name}: ${value || undefined}`;
   }
 
-  formatPropObject(obj: { [prop: string]: any }): string[] {
-    return Object.entries(obj).map(([k, v]) => this.formatProp(k, v));
+  formatPropObject(
+    obj: { [prop: string]: any },
+    attrsTranslationCtx: { [name: string]: string } | null,
+    translationCtx: string | null
+  ): string[] {
+    return Object.entries(obj).map(([k, v]) =>
+      this.formatProp(k, v, attrsTranslationCtx, translationCtx)
+    );
   }
 
   getPropString(props: string[], dynProps: string | null): string {
@@ -1181,7 +1200,9 @@ export class CodeGenerator {
     let { block } = ctx;
     // props
     const hasSlotsProp = "slots" in (ast.props || {});
-    const props: string[] = ast.props ? this.formatPropObject(ast.props) : [];
+    const props: string[] = ast.props
+      ? this.formatPropObject(ast.props, ast.propsTranslationCtx, ctx.translationCtx)
+      : [];
 
     // slots
     let slotDef: string = "";
@@ -1205,7 +1226,13 @@ export class CodeGenerator {
           params.push(`__scope: "${scope}"`);
         }
         if (ast.slots[slotName].attrs) {
-          params.push(...this.formatPropObject(ast.slots[slotName].attrs!));
+          params.push(
+            ...this.formatPropObject(
+              ast.slots[slotName].attrs!,
+              ast.slots[slotName].attrsTranslationCtx,
+              ctx.translationCtx
+            )
+          );
         }
         const slotInfo = `{${params.join(", ")}}`;
         slotStr.push(`'${slotName}': ${slotInfo}`);
@@ -1332,7 +1359,9 @@ export class CodeGenerator {
       key = this.generateComponentKey(key);
     }
 
-    const props = ast.attrs ? this.formatPropObject(ast.attrs) : [];
+    const props = ast.attrs
+      ? this.formatPropObject(ast.attrs, ast.attrsTranslationCtx, ctx.translationCtx)
+      : [];
     const scope = this.getPropString(props, dynProps);
     if (ast.defaultContent) {
       const name = this.compileInNewTarget("defaultContent", ast.defaultContent, ctx);
@@ -1365,6 +1394,15 @@ export class CodeGenerator {
     }
     return null;
   }
+  compileTTranslationContext(ast: ASTTranslationContext, ctx: Context): string | null {
+    if (ast.content) {
+      return this.compileAST(
+        ast.content,
+        Object.assign({}, ctx, { translationCtx: ast.translationCtx })
+      );
+    }
+    return null;
+  }
   compileTPortal(ast: ASTTPortal, ctx: Context): string {
     if (!this.staticDefs.find((d) => d.id === "Portal")) {
       this.staticDefs.push({ id: "Portal", expr: `app.Portal` });