with-output-whitespace

Introduce tag for local control of whitespace output.
Have a look at tests.
See Github issue #4

compiler.lisp

@@ -77,26 +77,28 @@
                                (coerce body 'list))
                for output := (emit elem)
                when output
-		 collect output))))
+                 collect output))))
     (let ((exprs (read-template-expressions (code tag))))
       (case (first exprs)
-	(ten/template::section ;; sections are a special case
+        (ten/template:with-output-whitespace ;; control whitespace output
+            (let ((*output-whitespace* (cadr exprs)))
+              `(,@exprs ,@(emit-body (body tag)))))
+        (ten/template::section ;; sections are a special case
          ;; push the section to the list of sections
          ;; to generate render-section methods later
          (push (list (second exprs)
                      (emit-body (body tag)))
                *sections*)
          `(ten/compiler::render-section ',(second exprs) ten/template::%ten-template %ten-stream))
-	(cl:if ;; check there's an else tag in body and emit
-	 (when (not (find-if (lambda (x) (typep x 'ten/parser::<else-tag>))
-			     (body tag)))
-	   (error "Missing {% else %} in {% if %} expression: ~a"
-		  tag))
-	 `(,@exprs ,@(emit-body (body tag))))
-	(t ;; otherwise, just emit
+        (cl:if ;; check there's an else tag in body and emit
+         (when (not (find-if (lambda (x) (typep x 'ten/parser::<else-tag>))
+                             (body tag)))
+           (error "Missing {% else %} in {% if %} expression: ~a"
+                  tag))
+         `(,@exprs ,@(emit-body (body tag))))
+        (t ;; otherwise, just emit
          `(,@exprs ,@(emit-body (body tag))))))))
 
-
 (defun control-element-p (element)
   (typep element '<control-tag>))
 
@@ -134,7 +136,7 @@
                                               (ten/template::%ten-template ,(getf *compiling-template* :name))
                                               %ten-stream)
                      (declare (ignore section))
-		     (declare (ignorable %ten-stream))
+                     (declare (ignorable %ten-stream))
                      (with-slots ,arg-names ten/template::%ten-template
                        ,@body))))))))
 

examples/with-output-whitespace.html

@@ -0,0 +1,22 @@
+{% template with-output-whitespace-test-1 (:output-whitespace nil) (data) %}
+{% loop for item in data do %}
+{{item.car}}    {{item.cdr}}
+{% end %}
+{% end %}
+
+{% template with-output-whitespace-test-2 (:output-whitespace nil) (data) %}
+{% loop for item in data do %}
+{% with-output-whitespace T %}{{item.car}}    {{item.cdr}}
+{% end %}
+{% end %}
+{% end %}
+
+{% template with-output-whitespace-test-3 (:output-whitespace nil) (data) %}
+{% loop for item in data do %}
+{% with-output-whitespace T %}{{item.car}}    {{item.cdr}}
+{% end %}
+{% end %}
+{% loop for item in data do %}
+{{item.car}}    {{item.cdr}}
+{% end %}
+{% end %}

package.lisp

@@ -22,6 +22,7 @@
            :super
            :section
            :comment
+           :with-output-whitespace
            :_
            :%ten-stream
            :*template-output*
@@ -49,6 +50,7 @@
                 :verbatim
                 :comment
                 :super
+                :with-output-whitespace
                 :section
                 :begin-raw
                 :begin-verb
@@ -64,6 +66,7 @@
            :comment
            :super
            :section
+           :with-output-whitespace
            :begin-raw
            :begin-verb
            :begin-verbatim

template.lisp

@@ -153,3 +153,7 @@ IMPORTANT: some of this macro arguments are processed by CALL-WITH-TEMPLATE-HEAD
     (progn
       (call-next-method)
       ""))
+
+(defmacro with-output-whitespace (value &body body)
+  `(let ((*output-whitespace* ,value))
+     ,@body))

ten.examples.asd

@@ -21,4 +21,5 @@
              (:ten-template "filters" :file-extension "html" :package :ten/examples)
              (:ten-template "escaping" :file-extension "html" :package :ten/examples)
              (:ten-template "control" :file-extension "html" :package :ten/examples)
+             (:ten-template "with-output-whitespace" :file-extension "html" :package :ten/examples)
              ))))

tests.lisp

@@ -31,7 +31,7 @@
 
 (def-test if-expression-test ()
   ;; {% if %} without {% else %} should fail to compile
-  (signals error 
+  (signals error
     (ten:compile-template "{% template if-test-1 () (locale) %}
 <html {% if locale %}lang=\"{{ locale }}\"{% end %}>
 {% end %}"))
@@ -45,3 +45,16 @@
     (ten:compile-template "{% template if-test-3 () (locale) %}
 <html {% when locale %}lang=\"{{ locale }}\"{% end %}>
 {% end %}")))
+
+(def-test with-output-whitespace-test ()
+  (is (string= (ten/examples:with-output-whitespace-test-1 '((:x . 1) (:y . 2)))
+               "X1Y2"))
+  (is (string= (ten/examples:with-output-whitespace-test-2 '((:x . 1) (:y . 2)))
+               "X    1
+Y    2
+")
+      (is (string= (ten/examples:with-output-whitespace-test-3 '((:x . 1) (:y . 2)))
+                   "X    1
+Y    2
+X1Y2"))
+      ))