Index: raster/rt_pg/rtpostgis.sql.in.c
===================================================================
--- raster/rt_pg/rtpostgis.sql.in.c     (revision 7923)
+++ raster/rt_pg/rtpostgis.sql.in.c     (working copy)
@@ -1584,18 +1584,18 @@
 -----------------------------------------------------------------------
 -- MapAlgebra
 -----------------------------------------------------------------------
--- This function can not be STRICT, because nodatavalueexpr can be NULL (could be just '' though)
+-- This function can not be STRICT, because nodatavaluerepl can be NULL (could be just '' though)
 -- or pixeltype can not be determined (could be st_bandpixeltype(raster, band) though)
 CREATE OR REPLACE FUNCTION st_mapalgebra(rast raster, band integer,
-        expression text, nodatavalueexpr text DEFAULT NULL, pixeltype text DEFAULT NULL)
+        expression text, nodatavaluerepl text DEFAULT NULL, pixeltype text DEFAULT NULL)
     RETURNS raster
     AS 'MODULE_PATHNAME', 'RASTER_mapAlgebra'
     LANGUAGE 'C' IMMUTABLE;

--- This function can not be STRICT, because nodatavalueexpr can be NULL (could be just '' though)
+-- This function can not be STRICT, because nodatavaluerepl can be NULL (could be just '' though)
 -- or pixeltype can not be determined (could be st_bandpixeltype(raster, band) though)
 CREATE OR REPLACE FUNCTION st_mapalgebra(rast raster, expression text,
-        nodatavalueexpr text DEFAULT NULL, pixeltype text DEFAULT NULL)
+        nodatavaluerepl text DEFAULT NULL, pixeltype text DEFAULT NULL)
     RETURNS raster
     AS $$ SELECT st_mapalgebra($1, 1, $2, $3, $4) $$
     LANGUAGE SQL;
Index: raster/rt_pg/rt_pg.c
===================================================================
--- raster/rt_pg/rt_pg.c        (revision 7923)
+++ raster/rt_pg/rt_pg.c        (working copy)
@@ -2462,7 +2462,7 @@
     char *initexpr = NULL;
     char *initndvexpr = NULL;
     char *expression = NULL;
-    char *nodatavalueexpr = NULL;
+    char *nodatavaluerepl = NULL;
     rt_pixtype newpixeltype;
     int skipcomputation = 0;
     char strnewnodatavalue[50];
@@ -2678,21 +2678,21 @@


     /**
-     * Optimization: If a nodatavalueexpr is provided, recompute the initial
+     * Optimization: If a nodatavaluerepl is provided, recompute the initial
      * value. Then, we can initialize the raster with this value and skip the
      * computation of nodata values one by one in the main computing loop
      **/
     if (!PG_ARGISNULL(3)) {
-        nodatavalueexpr = text_to_cstring(PG_GETARG_TEXT_P(3));
-        len = strlen("SELECT ") + strlen(nodatavalueexpr);
+        nodatavaluerepl = text_to_cstring(PG_GETARG_TEXT_P(3));
+        len = strlen("SELECT ") + strlen(nodatavaluerepl);
         initndvexpr = (char *)palloc(len + 1);
         strncpy(initndvexpr, "SELECT ", strlen("SELECT "));
-        strncpy(initndvexpr + strlen("SELECT "), strtoupper(nodatavalueexpr),
-                strlen(nodatavalueexpr));
+        strncpy(initndvexpr + strlen("SELECT "), strtoupper(nodatavaluerepl),
+                strlen(nodatavaluerepl));
         initndvexpr[len] = '\0';

-        //lwfree(nodatavalueexpr);
-        //nodatavalueexpr = NULL;
+        //lwfree(nodatavaluerepl);
+        //nodatavaluerepl = NULL;

         /* Replace RAST, if present, for NODATA value, to eval the expression */
         if (strstr(initndvexpr, "RAST")) {
@@ -2759,7 +2759,7 @@

     /**
      * Optimization: If the raster is only filled with nodata values return
-     * right now a raster filled with the nodatavalueexpr
+     * right now a raster filled with the nodatavaluerepl
      * TODO: Call rt_band_check_isnodata instead?
      **/
     if (rt_band_get_isnodata_flag(band)) {
@@ -2793,12 +2793,12 @@


     /**
-     * Optimization: If expression resume to 'RAST' and nodatavalueexpr is NULL
+     * Optimization: If expression resume to 'RAST' and nodatavaluerepl is NULL
      * or also equal to 'RAST', we can just return the band from the original
      * raster
      **/
     if (initexpr != NULL && !strcmp(initexpr, "SELECT RAST") &&
-                   (nodatavalueexpr  == NULL || !strcmp(initndvexpr, "SELECT RAST"))) {
+                   (nodatavaluerepl  == NULL || !strcmp(initndvexpr, "SELECT RAST"))) {
             //(initndvexpr == NULL || !strcmp(initndvexpr, "SELECT RAST"))) {

         POSTGIS_RT_DEBUGF(3, "RASTER_mapAlgebra: Expression resumes to RAST. "
@@ -2875,7 +2875,7 @@
          * new raster
          **/
         //if (initndvexpr == NULL) {
-        if (nodatavalueexpr == NULL) {
+        if (nodatavaluerepl == NULL) {
             newinitialvalue = newval;
             skipcomputation = 2;
         }