Lots of work as usual :-)

Lots of work as usual :-)

Cell lookup is still broken.
More functions!  COUNT, AVERAGE, AND, OR.

Changed the function framework: it is now easier to write
functions that take multiple arguments.

Added some documentation on writing functions.

Miguel.

ChangeLog-1999-07-09

 1998-08-06  Miguel de Icaza  <miguel@nuclecu.unam.mx>
 
+	* src/fn-math.c: Moved the math functions to this file. 
+	(gnumeric_sum): Make it use the new function_iterate_argument_values.
+	(gnumeric_and): Implement AND function.
+	(gnumeric_or):  Implement OR function.
+
+	* src/func.c (function_iterate_argument_values): New function to
+	ease the creation of functions with multiple arguments.  It
+	generates Value * for a list of expressions that might include
+	arrays and cell ranges. 
+
+	* src/expr.c (cell_get_col_row): New routine to get the absolute
+	cordinates with respect to an evaluation column and row.
+
+	* src/parser.y (return_symbol): Support for constants.
+
+	* src/expr.c (value_copy_to): Support for making Value copies
+	(only used for our constants actually).
+
+	* src/symbol.c (init_constants): Declare TRUE and FALSE.
+
 	* src/sheet.c (sheet_selection_changed_hook): Autocomputation
 	routine.  Whenever selection changes this routine will execute an
 	arbitrary expression (kept in the workbook) and display the
@@ -64,7 +84,6 @@
 
 	* src/parser.y (alloc_glist): Keep track of argument lists. 
 
-	* 
 1998-07-30  Federico Mena Quintero  <federico@nuclecu.unam.mx>
 
 	* src/sheet.c (canvas_bar_realized): 

ChangeLog-2000-02-23

 1998-08-06  Miguel de Icaza  <miguel@nuclecu.unam.mx>
 
+	* src/fn-math.c: Moved the math functions to this file. 
+	(gnumeric_sum): Make it use the new function_iterate_argument_values.
+	(gnumeric_and): Implement AND function.
+	(gnumeric_or):  Implement OR function.
+
+	* src/func.c (function_iterate_argument_values): New function to
+	ease the creation of functions with multiple arguments.  It
+	generates Value * for a list of expressions that might include
+	arrays and cell ranges. 
+
+	* src/expr.c (cell_get_col_row): New routine to get the absolute
+	cordinates with respect to an evaluation column and row.
+
+	* src/parser.y (return_symbol): Support for constants.
+
+	* src/expr.c (value_copy_to): Support for making Value copies
+	(only used for our constants actually).
+
+	* src/symbol.c (init_constants): Declare TRUE and FALSE.
+
 	* src/sheet.c (sheet_selection_changed_hook): Autocomputation
 	routine.  Whenever selection changes this routine will execute an
 	arbitrary expression (kept in the workbook) and display the
@@ -64,7 +84,6 @@
 
 	* src/parser.y (alloc_glist): Keep track of argument lists. 
 
-	* 
 1998-07-30  Federico Mena Quintero  <federico@nuclecu.unam.mx>
 
 	* src/sheet.c (canvas_bar_realized): 

OChangeLog-1999-07-09

 1998-08-06  Miguel de Icaza  <miguel@nuclecu.unam.mx>
 
+	* src/fn-math.c: Moved the math functions to this file. 
+	(gnumeric_sum): Make it use the new function_iterate_argument_values.
+	(gnumeric_and): Implement AND function.
+	(gnumeric_or):  Implement OR function.
+
+	* src/func.c (function_iterate_argument_values): New function to
+	ease the creation of functions with multiple arguments.  It
+	generates Value * for a list of expressions that might include
+	arrays and cell ranges. 
+
+	* src/expr.c (cell_get_col_row): New routine to get the absolute
+	cordinates with respect to an evaluation column and row.
+
+	* src/parser.y (return_symbol): Support for constants.
+
+	* src/expr.c (value_copy_to): Support for making Value copies
+	(only used for our constants actually).
+
+	* src/symbol.c (init_constants): Declare TRUE and FALSE.
+
 	* src/sheet.c (sheet_selection_changed_hook): Autocomputation
 	routine.  Whenever selection changes this routine will execute an
 	arbitrary expression (kept in the workbook) and display the
@@ -64,7 +84,6 @@
 
 	* src/parser.y (alloc_glist): Keep track of argument lists. 
 
-	* 
 1998-07-30  Federico Mena Quintero  <federico@nuclecu.unam.mx>
 
 	* src/sheet.c (canvas_bar_realized): 

OChangeLog-2000-02-23

 1998-08-06  Miguel de Icaza  <miguel@nuclecu.unam.mx>
 
+	* src/fn-math.c: Moved the math functions to this file. 
+	(gnumeric_sum): Make it use the new function_iterate_argument_values.
+	(gnumeric_and): Implement AND function.
+	(gnumeric_or):  Implement OR function.
+
+	* src/func.c (function_iterate_argument_values): New function to
+	ease the creation of functions with multiple arguments.  It
+	generates Value * for a list of expressions that might include
+	arrays and cell ranges. 
+
+	* src/expr.c (cell_get_col_row): New routine to get the absolute
+	cordinates with respect to an evaluation column and row.
+
+	* src/parser.y (return_symbol): Support for constants.
+
+	* src/expr.c (value_copy_to): Support for making Value copies
+	(only used for our constants actually).
+
+	* src/symbol.c (init_constants): Declare TRUE and FALSE.
+
 	* src/sheet.c (sheet_selection_changed_hook): Autocomputation
 	routine.  Whenever selection changes this routine will execute an
 	arbitrary expression (kept in the workbook) and display the
@@ -64,7 +84,6 @@
 
 	* src/parser.y (alloc_glist): Keep track of argument lists. 
 
-	* 
 1998-07-30  Federico Mena Quintero  <federico@nuclecu.unam.mx>
 
 	* src/sheet.c (canvas_bar_realized): 

doc/functions.sgml

+
+Function: AND
+
+Syntax:   AND(b1, b2, ...)
+
+Implements the logical AND function: the result is TRUE if all of the
+expression evaluate to TRUE, otherwise it returns FALSE.
+
+b1, trough bN are expressions that should evaluate to TRUE or FALSE.
+If an integer or floating point value is provided zero is considered
+FALSE and anything else is TRUE.
+
+If the values contain strings or empty cells those values are
+ignored.  If no logical values are provided, then the error '#VALUE!'
+is returned. 
+
+See also: OR.
+
+
+
+-----------------------
+Function: AVERAGE
+
+Syntax:   AVERAGE(value1, value2,...)
+
+Computes the average of all the values and cells referenced in the
+argument list.  This is equivalent to the sum of the arguments divided
+by the count of the arguments.
+
+See also: SUM, COUNT
+-----------------------
+Function: OR
+
+Syntax:   OR(b1, b2, ...)
+
+Implements the logical OR function: the result is TRUE if any of the
+values evaluated to TRUE.
+
+b1, trough bN are expressions that should evaluate to TRUE or FALSE.
+If an integer or floating point value is provided zero is considered
+FALSE and anything else is TRUE.
+
+If the values contain strings or empty cells those values are
+ignored.  If no logical values are provided, then the error '#VALUE!'
+is returned. 
+
+See also: AND
+
+-----------------------
\ No newline at end of file

doc/writing-functions.smgl

+
+Writing builtin functions for Gnumeric:
+---------------------------------------
+
+Functions in Gnumeric should be registered in the symbol table, to
+register a function you just need to prepare a function definition
+record. 
+
+For example, a simple routine to sum two numbers, you would do:
+
+char *help_add2numbers = "ADD2NUMBERS: Adds two numbers";
+
+FunctionDefinition add_two_numbers = 
+{ "add2numers", "ff", "number1,number2", help_add2numbers, NULL, add2numbers }
+
+The first C declaration defines the HELP associated with this
+function.
+
+The second declaration is our function definition record:  the name of
+the function is the first parameter (this is how the function will be
+exposed to Gnumeric), the next parameter tells gnumeric that we are
+expecting two floating point arguments.  The third parameter describes
+the symbolic names for the arguments (in case our function supports
+them, this allows users to specify named paramters); The fourth
+parameter links in the help description.
+
+Now, our routine is pretty simple: it will always require 2 arguments
+to be passed, so we can let Gnumeric deal with argument count and we
+can let the Gnumeric engine compute the values in the expression for
+us.  So, for this case we leave the fift parameter set as NULL and set
+the sixth parameter to point to the function that will do the function
+evaluation. 
+
+Now, to register the function we just do:
+
+register_add2numbers ()
+{
+	symbol_install (add_two_numbers.name, SYMBOL_FUNCTION, &add_two_numbers);
+}
+
+When the user calls the function "ADD2NUMBERS" in a Gnumeric
+expression, our routine will be invoked, this is how the add2numbers
+function signature looks like:
+
+static Value *
+add2numbers (Value *argv [], char **error_string)
+{
+	
+}
+
+The function should return a newly allocated Value structure.
+Arguments are passed in the argv array and they contain Value
+structures (look in gnumeric/src/expr.h for the definition of the
+Value structure).
+
+Here is the actual implementation:
+
+static Value *
+add2numbers (Value *argv [], char **error_string)
+{
+	Value *result;
+	float number_a, number_b;
+
+	switch (argv [0].type){
+	case VALUE_INTEGER:
+		number_a = argv [0].v.v_int;
+		break;
+
+	case VALUE_FLOAT:
+		number_a = argv [0].v.v_float;
+		break;
+
+	default:
+		*error_string = "Invalid argument type";
+		return NULL;
+	}
+
+	switch (argv [1].type){
+	case VALUE_INTEGER:
+		number_a = argv [1].v.v_int;
+		break;
+
+	case VALUE_FLOAT:
+		number_a = argv [1].v.v_float;
+		break;
+
+	default:
+		*error_string = "Invalid argument type";
+		return NULL;
+	}
+
+	/* 
+	 * the line below is equivalent to:
+	 * result = (Value *) malloc (sizeof (Value));
+	 *
+	 */
+	result = g_new (Value, 1);
+	result->type = VALUE_FLOAT;
+	result->v.v_float = number_a + number_b;
+
+	return result;
+}
+
+Note that the typechecking is done in the routine itself, it is not
+done by the upper layers.  If there is an error during the function
+processing, *error_string should be set to the error message
+describing what went wrong and the NULL value should be returned.
+
+Functions with a variable number of arguments
+---------------------------------------------
+
+Gnumeric supports two types of functions: those that take a fixed
+number of arguments and those that do take a variable number of
+arguments.  In the former case, the Gnumeric engine does some work to
+simplify function coding, in the later case, the function writer is
+pretty much presented with the raw expression tree data as a list. 
+
+If you want to implement a function that takes a variable number of
+arguments you have to change your FunctionDefinition:  instead of
+setting the fifth parameter as NULL and the sixth pointing to your
+function, you should set the sixth parameter to NULL and you fill in
+the fifth parameter, like this:
+
+char *help_factadd = "Adds all of its arguments";
+
+{ "addall", "", "",  help_addall, addall, NULL }
+
+We will now implement addall, a function that takes any number and
+kind of arguments: strings, integers, floating point numbers, arrays
+and cell ranges.  
+
+This is a simple usage of addall, lets imagine cell A1 contains the
+value 5 and the cell A2 contains the value 3.
+
+addall (1)			returns 1
+addall (1,2)			returns 3
+addall (a1:a3)			returns 8
+addall (a1:a3,1)		returns 9
+
+Here is the function signature for addall:
+
+Value *
+addall (void *sheet, GList *expr_node_list, int eval_col, 
+	int eval_row, char **error_string)
+
+As usual, this routine would return a newly allocated Value or NULL if
+an error is found (and in that case, error_string would be set to
+point to a message describing the problem).
+
+The first argument points to a (Sheet *) structure, and the second
+argument is a linked list (a GList) that contains (ExprTree *) nodes.
+
+The eval_col and eval_row parameters are used to inform the function
+in which context the expression should be evaluated (ie, from which
+cell it is being invoked) and it is used when invoking the expr_eval
+function.
+

src/Makefile.am

@@ -20,6 +20,7 @@ GNUMERIC_BASE_SOURCES =		\
 	func.c			\
 	func.h			\
 	fn-sheet.c		\
+	fn-math.c		\
 	gnumeric-sheet.c	\
 	gnumeric-sheet.h	\
 	gnumeric.h		\

src/cell.c

@@ -28,7 +28,11 @@ sheet_cell_foreach_range (Sheet *sheet,
 			if (ri->pos > end_row)
 				break;
 
-			(*callback)(sheet, (Cell *) ri->data);
+			v = (*callback)(sheet, (Cell *) ri->data);
+
+			/* If the callback wishes to stop, return */
+			if (v)
+				return;
 		}
 	}
 }

src/expr.c

 #include <config.h>
 #include <gnome.h>
 #include "gnumeric.h"
+#include "expr.h"
 
 char *parser_expr;
 ParseErr parser_error;
@@ -100,6 +101,8 @@ expr_tree_unref (ExprTree *tree)
 void
 value_release (Value *value)
 {
+	g_return_if_fail (value != NULL);
+	
 	switch (value->type){
 	case VALUE_STRING:
 		string_unref (value->v.str);
@@ -130,6 +133,36 @@ value_release (Value *value)
 	g_free (value);
 }
 
+/*
+ * Copies a Value.
+ */
+void
+value_copy_to (Value *dest, Value *source)
+{
+	g_return_if_fail (dest != NULL);
+	g_return_if_fail (source != NULL);
+
+	dest->type = source->type;
+	
+	switch (source->type){
+	case VALUE_STRING:
+		dest->v.str = source->v.str;
+		string_ref (dest->v.str);
+		break;
+
+	case VALUE_INTEGER:
+		dest->v.v_int = source->v.v_int;
+		break;
+
+	case VALUE_FLOAT:
+		dest->v.v_float = source->v.v_float;
+		break;
+
+	default:
+		g_warning ("value_copy_to: VALUE type not yet supported\n");
+	}
+}
+
 /*
  * Casts a value to float if it is integer, and returns
  * a new Value * if required
@@ -309,6 +342,11 @@ eval_expr (void *asheet, ExprTree *tree, int eval_col, int eval_row, char **erro
 {
 	Value *a, *b, *res;
 	Sheet *sheet = asheet;
+
+	g_return_val_if_fail (tree != NULL, NULL);
+	g_return_val_if_fail (asheet != NULL, NULL);
+	g_return_val_if_fail (error_string != NULL, NULL);
+	g_return_val_if_fail (IS_SHEET (asheet), NULL);
 	
 	switch (tree->oper){
 	case OP_EQUAL:
@@ -502,15 +540,7 @@ eval_expr (void *asheet, ExprTree *tree, int eval_col, int eval_row, char **erro
 		}
 
 		ref = &tree->u.constant->v.cell;
-		if (ref->col_relative)
-			col = eval_col + ref->col;
-		else
-			col = ref->col;
-
-		if (ref->row_relative)
-			row = eval_row + ref->row;
-		else
-			row = ref->row;
+		cell_get_abs_col_row (&tree->u.constant->v.cell, eval_col, eval_row, &col, &row);
 		
 		cell = sheet_cell_get (sheet, col, row);
 		if (!cell)
@@ -551,3 +581,20 @@ eval_expr (void *asheet, ExprTree *tree, int eval_col, int eval_row, char **erro
 	*error_string = _("Unknown evaluation error");
 	return NULL;
 }
+
+void
+cell_get_abs_col_row (CellRef *cell_ref, int eval_col, int eval_row, int *col, int *row)
+{
+	g_return_if_fail (cell_ref != NULL);
+
+	if (cell_ref->col_relative)
+		*col = eval_col + cell_ref->col;
+	else
+		*col = cell_ref->col;
+
+	if (cell_ref->row_relative)
+		*row = eval_row + cell_ref->row;
+	else
+		*row = cell_ref->row;
+}
+

src/expr.h

@@ -119,10 +119,11 @@ typedef struct {
 	 * f for float
 	 * s for string
 	 * b for boolean
+	 * ? for any kind
 	 */
 	char  *args;
 	char  *named_arguments;
-	
+	char  **help;
 	Value *(*expr_fn)(void *sheet, GList *expr_node_list, int eval_col, int eval_row, char **error_string);
 	
 	Value *(*fn)(Value *argv [], char **error_string);
@@ -134,26 +135,32 @@ extern ParseErr  parser_error;
 extern ExprTree *parser_result;
 extern int       parser_col, parser_row;
 
-ExprTree   *expr_parse_string   (char *expr, int col, int row, char **error_msg);
-void        expr_tree_ref       (ExprTree *tree);
-void        expr_tree_unref     (ExprTree *tree);
-
-/* Do not use this routine, it is intended to be used internally */
-void        eval_expr_release   (ExprTree *tree);
-
-Value      *eval_expr           (void *asheet, ExprTree *tree,
-				 int  col, int row,
-				 char **error_string);
-
-void        value_release       (Value *value);
-Value      *value_cast_to_float (Value *v);
-int         value_get_bool      (Value *v, int *err);
-float_t     value_get_as_double (Value *v);
+void        cell_get_abs_col_row (CellRef *cell_ref, int eval_col, int eval_row, int *col, int *row);
 
-void        value_dump          (Value *value);
-char       *value_string        (Value *value);
+ExprTree   *expr_parse_string    (char *expr, int col, int row, char **error_msg);
+void        expr_tree_ref        (ExprTree *tree);
+void        expr_tree_unref      (ExprTree *tree);
 
-int         yyparse             (void);
-void        functions_init      (void);
+/* Do not use this routine, it is intended to be used internally */
+void        eval_expr_release    (ExprTree *tree);
+				 
+Value      *eval_expr            (void *asheet, ExprTree *tree,
+				  int  col, int row,
+				  char **error_string);
+				 
+void        value_release        (Value *value);
+Value      *value_cast_to_float  (Value *v);
+int         value_get_bool       (Value *v, int *err);
+float_t     value_get_as_double  (Value *v);
+void        value_copy_to        (Value *dest, Value *source);
+				 
+void        value_dump           (Value *value);
+char       *value_string         (Value *value);
+				 
+int         yyparse              (void);
+
+/* Setup of the symbol table */
+void        functions_init       (void);
+void        constants_init       (void);
 
 #endif

src/fn-sheet.c

@@ -100,28 +100,10 @@ gnumeric_selection (void *tsheet, GList *expr_node_list, int eval_col, int eval_
 	return value;
 }
 
-static Value *
-gnumeric_count (void *tsheet, GList *expr_node_list, int eval_col, int eval_row, char **error_string)
-{
-	*error_string = "not yet implemented";
-
-	return NULL;
-}
-
-static Value *
-gnumeric_average (void *tsheet, GList *expr_node_list, int eval_col, int eval_row, char **error_string)
-{
-	*error_string = "not yet implemented";
-	
-	return NULL;
-}
-
 FunctionDefinition sheet_functions [] = {
-	{ "if",     0,       "logical_test,value_if_true,value_if_false",
+	{ "if",     0,       "logical_test,value_if_true,value_if_false", NULL,
 	  gnumeric_if, NULL },
-	{ "selection", 0,    "", gnumeric_selection, NULL },
-	{ "count",     0,    "", gnumeric_count,     NULL },
-	{ "average",   0,    "", gnumeric_average,   NULL },
+	{ "selection", 0,    "", NULL, gnumeric_selection, NULL },
 	{ NULL, NULL }
 };
 

src/func.c

@@ -14,439 +14,126 @@
 #include "utils.h"
 #include "func.h"
 
-static Value *
-gnumeric_abs (Value *argv [], char **error_string)
-{
-	Value *v = g_new (Value, 1);
-
-	v->type = VALUE_FLOAT;
-	v->v.v_float = fabs (value_get_as_double (argv [0]));
-
-	return v;
-}
-
-static Value *
-gnumeric_acos (Value *argv [], char **error_string)
-{
-	Value *v;
-	float_t t;
-
-	t = value_get_as_double (argv [0]);
-	if ((t < -1.0) || (t > 1.0)){
-		*error_string = _("acos - domain error");
-		return NULL;
-	}
-	v = g_new (Value, 1);
-	v->type = VALUE_FLOAT;
-	v->v.v_float = acos (t);
-
-	return v;
-}
-
-static Value *
-gnumeric_acosh (Value *argv [], char **error_string)
-{
-	Value *v;
-	float_t t;
-
-	t = value_get_as_double (argv [0]);
-	if (t < 1.0){
-		*error_string = _("acosh - domain error");
-		return NULL;
-	}
-	v = g_new (Value, 1);
-	v->type = VALUE_FLOAT;
-	v->v.v_float = acosh (t);
-
-	return v;
-}
-
-static Value *
-gnumeric_asin (Value *argv [], char **error_string)
-{
-	Value *v;
-	float_t t;
-
-	t = value_get_as_double (argv [0]);
-	if ((t < -1.0) || (t > 1.0)){
-		*error_string = _("asin - domain error");
-		return NULL;
-	}
-	v = g_new (Value, 1);
-	v->type = VALUE_FLOAT;
-	v->v.v_float = asin (t);
-
-	return v;
-}
-
-static Value *
-gnumeric_asinh (Value *argv [], char **error_string)
-{
-	Value *v;
-
-	v = g_new (Value, 1);