Addition of boolean template functions and, or, not. Change documentation to include them. Add a function classification summary to the documentation.

src/calibre/manual/template_lang.rst

@@ -229,13 +229,14 @@ For various values of series_index, the program returns:
 
 The following functions are available in addition to those described in single-function mode. Remember from the example above that the single-function mode functions require an additional first parameter specifying the field to operate on. With the exception of the ``id`` parameter of assign, all parameters can be statements (sequences of expressions):
 
+    * ``and(value, value, ...)`` -- returns the string "1" if all values are not empty, otherwise returns the empty string. This function works well with test or first_non_empty. You can have as many values as you want.
     * ``add(x, y)`` -- returns x + y. Throws an exception if either x or y are not numbers.
     * ``assign(id, val)`` -- assigns val to id, then returns val. id must be an identifier, not an expression
     * ``booksize()`` -- returns the value of the |app| 'size' field. Returns '' if there are no formats.
     * ``cmp(x, y, lt, eq, gt)`` -- compares x and y after converting both to numbers. Returns ``lt`` if x < y. Returns ``eq`` if x == y. Otherwise returns ``gt``.
     * ``divide(x, y)`` -- returns x / y. Throws an exception if either x or y are not numbers.
     * ``field(name)`` -- returns the metadata field named by ``name``.
-    * ``first_non_empty(value, value, ...) -- returns the first value that is not empty. If all values are empty, then the empty value is returned. You can have as many values as you want.
+    * ``first_non_empty(value, value, ...)`` -- returns the first value that is not empty. If all values are empty, then the empty value is returned. You can have as many values as you want.
     * ``format_date(x, date_format)`` -- format_date(val, format_string) -- format the value, which must be a date field, using the format_string, returning a string. The formatting codes are::
     
         d    : the day as number without a leading zero (1 to 31)
@@ -251,7 +252,9 @@ The following functions are available in addition to those described in single-f
         iso  : the date with time and timezone. Must be the only format present.
     
     * ``eval(string)`` -- evaluates the string as a program, passing the local variables (those ``assign`` ed to). This permits using the template processor to construct complex results from local variables.
+    * ``not(value)`` -- returns the string "1" if the value is empty, otherwise returns the empty string. This function works well with test or first_non_empty. You can have as many values as you want.
     * ``multiply(x, y)`` -- returns x * y. Throws an exception if either x or y are not numbers.
+    * ``or(value, value, ...)`` -- returns the string "1" if any value is not empty, otherwise returns the empty string. This function works well with test or first_non_empty. You can have as many values as you want.
     * ``print(a, b, ...)`` -- prints the arguments to standard output. Unless you start calibre from the command line (``calibre-debug -g``), the output will go to a black hole.
     * ``raw_field(name)`` -- returns the metadata field named by name without applying any formatting.
     * ``strcat(a, b, ...)`` -- can take any number of arguments. Returns a string formed by concatenating all the arguments.
@@ -259,7 +262,22 @@ The following functions are available in addition to those described in single-f
     * ``substr(str, start, end)`` -- returns the ``start``'th through the ``end``'th characters of ``str``. The first character in ``str`` is the zero'th character. If end is negative, then it indicates that many characters counting from the right. If end is zero, then it indicates the last character. For example, ``substr('12345', 1, 0)`` returns ``'2345'``, and ``substr('12345', 1, -1)`` returns ``'234'``.
     * ``subtract(x, y)`` -- returns x - y. Throws an exception if either x or y are not numbers.
     * ``template(x)`` -- evaluates x as a template. The evaluation is done in its own context, meaning that variables are not shared between the caller and the template evaluation. Because the `{` and `}` characters are special, you must use `[[` for the `{` character and `]]` for the '}' character; they are converted automatically. For example, ``template('[[title_sort]]') will evaluate the template ``{title_sort}`` and return its value.
+    
+Function classification summary:
 
+    * Get values from metadata: ``field``. ``raw_field``. In some situations, ``lookup`` can be used in place of ``field``.
+    * Arithmetic: ``add``, ``subtract``, ``multiply``, ``divide``
+    * Boolean: ``and``, ``or``, ``not``. The function ``if_empty`` is similar to ``and`` called with one argument.
+    * If-then-else: ``contains``, ``test``
+    * Iterating over values: ``first_non_empty``, ``lookup``, ``switch``
+    * List lookup: ``in_list``, ``list_item``, ``select``, 
+    * List manipulation: ``count``, ``sublist``, ``subitems``
+    * Recursion: ``eval``, ``template``
+    * Relational: ``cmp`` , ``strcmp`` for strings
+    * String case changes: ``lowercase``, ``uppercase``, ``titlecase``, ``capitalize``
+    * String manipulation: ``re``, ``shorten``, ``substr``
+    * Other: ``assign``, ``booksize``, ``print``, ``format_date``, 
+        
 .. _general_mode:
 
 Using general program mode

src/calibre/utils/formatter_functions.py

@@ -594,7 +594,56 @@ class BuiltinFirstNonEmpty(BuiltinFormatterFunction):
             i += 1
         return ''
 
+class BuiltinAnd(BuiltinFormatterFunction):
+    name = 'and'
+    arg_count = -1
+    doc = _('and(value, value, ...) -- '
+            'returns the string "1" if all values are not empty, otherwise '
+            'returns the empty string. This function works well with test or '
+            'first_non_empty. You can have as many values as you want.')
+
+    def evaluate(self, formatter, kwargs, mi, locals, *args):
+        i = 0
+        while i < len(args):
+            if not args[i]:
+                return ''
+            i += 1
+        return '1'
+
+class BuiltinOr(BuiltinFormatterFunction):
+    name = 'or'
+    arg_count = -1
+    doc = _('or(value, value, ...) -- '
+            'returns the string "1" if any value is not empty, otherwise '
+            'returns the empty string. This function works well with test or '
+            'first_non_empty. You can have as many values as you want.')
+
+    def evaluate(self, formatter, kwargs, mi, locals, *args):
+        i = 0
+        while i < len(args):
+            if args[i]:
+                return '1'
+            i += 1
+        return ''
+
+class BuiltinNot(BuiltinFormatterFunction):
+    name = 'not'
+    arg_count = 1
+    doc = _('not(value) -- '
+            'returns the string "1" if the value is empty, otherwise '
+            'returns the empty string. This function works well with test or '
+            'first_non_empty. You can have as many values as you want.')
+
+    def evaluate(self, formatter, kwargs, mi, locals, *args):
+        i = 0
+        while i < len(args):
+            if args[i]:
+                return '1'
+            i += 1
+        return ''
+
 builtin_add         = BuiltinAdd()
+builtin_and         = BuiltinAnd()
 builtin_assign      = BuiltinAssign()
 builtin_booksize    = BuiltinBooksize()
 builtin_capitalize  = BuiltinCapitalize()
@@ -612,6 +661,8 @@ builtin_list_item   = BuiltinListitem()
 builtin_lookup      = BuiltinLookup()
 builtin_lowercase   = BuiltinLowercase()
 builtin_multiply    = BuiltinMultiply()
+builtin_not         = BuiltinNot()
+builtin_or          = BuiltinOr()
 builtin_print       = BuiltinPrint()
 builtin_raw_field   = BuiltinRaw_field()
 builtin_re          = BuiltinRe()