diff --git a/vpi/table_mod.c b/vpi/table_mod.c
index ff2e09070..dc41ae03e 100644
--- a/vpi/table_mod.c
+++ b/vpi/table_mod.c
@@ -348,7 +348,7 @@ static unsigned initialize_control_fields(vpiHandle callh, p_table_mod table,
       table->have_ctl = 1;
 
 	/* Look for the dependent data field. */
-      cp = index(control, ';');
+      cp = strchr(control, ';');
       if (cp) {
 	    size_t len;
 	    unsigned long val;
@@ -385,7 +385,7 @@ static unsigned initialize_control_fields(vpiHandle callh, p_table_mod table,
 	/* Find the number of interpolation/extrapolation control fields. */
       num_fields = 1;
       cp = control;
-      while ((cp = index(cp, ','))) {
+      while ((cp = strchr(cp, ','))) {
 	    cp += 1;
 	    num_fields += 1;
       }
diff --git a/vpi/table_mod_parse.y b/vpi/table_mod_parse.y
index d2c004c5a..700d1265c 100644
--- a/vpi/table_mod_parse.y
+++ b/vpi/table_mod_parse.y
@@ -24,21 +24,85 @@
 #include "table_mod.h"
 #include "ivl_alloc.h"
 
+/*
+ * The number of parse errors encountered while parsing the data file.
+ */
 static unsigned errors = 0;
+
+/*
+ * The minimum number of columns needed in the data file to satisfy the
+ * control string/input variable requirements.
+ */
 static unsigned minimum_columns;
+
+/*
+ * The number of independent values we expect to keep based on the control
+ * string/independent variables.
+ */
 static unsigned indep_values;
+
+/*
+ * The total number of independent columns to expect. This includes any
+ * ignored columns.
+ */
 static unsigned indep_columns;
+
+/*
+ * The zero based dependent column location. This is just minimum_columns - 1.
+ */
 static unsigned dep_column;
+
+/*
+ * The number of columns to expect in this data file. This must be
+ * greater than or equal to the minimum_columns above.
+ */
 static unsigned number_of_columns = 0;
+
+/*
+ * The number of columns that this point currently has.
+ */
 static unsigned cur_columns;
+
+/*
+ * The zero based current independent value we are looking for.
+ */
 static unsigned cur_value;
+
+/*
+ * The usable values for this point. The independent values are first and
+ * the dependent value is the last entry.
+ */
 static double *values;
+
+/*
+ * The name of the file we are getting data from.
+ */
 static const char *in_file_name;
+
+/*
+ * The table structure that we are getting data for.
+ */
 static p_table_mod table_def;
 
+/*
+ * The lexor and error routines.
+ */
 extern int tblmodlex(void);
 static void yyerror(const char *fmt, ...);
 
+static void process_point()
+{
+      assert(cur_value == indep_values);
+  #if 0
+      unsigned idx;
+      fprintf(stderr, "%#g", values[0]);
+      for (idx = 1; idx < indep_values; idx += 1) {
+	    fprintf(stderr, ", %#g", values[idx]);
+      }
+      fprintf(stderr, " => %#g\n", values[indep_values]);
+  #endif
+}
+
 %}
 
 %locations
@@ -52,19 +116,23 @@ static void yyerror(const char *fmt, ...);
 
 %%
 
+  /*
+   * A table is just a bunch of points. The lexor ignores any comments.
+   */
 table : point
       | table point
 
+  /*
+   * An individual point is just a bunch of columns followed by one or more
+   * end of line characters.
+   */
 point : columns END_LINE
       {
-  #if 0
-    unsigned idx;
-    fprintf(stderr, "%#g", values[0]);
-    for (idx = 1; idx < indep_values; idx += 1) {
-      fprintf(stderr, ", %#g", values[idx]);
-    }
-    fprintf(stderr, " => %#g\n", values[indep_values]);
-  #endif
+	      /*
+	       * If the number of columns has been defined then we must have
+	       * enough columns and we expect every line to have the same
+	       * number of columns.
+	       */
 	    if (number_of_columns) {
 		  if (cur_columns < minimum_columns) {
 			yyerror("Found %u columns, need at least %u.",
@@ -72,15 +140,26 @@ point : columns END_LINE
 		  } else if (cur_columns != number_of_columns) {
 			yyerror("Found %u columns, expected %u.",
 			        cur_columns, number_of_columns);
-		  }
+		  } else process_point();
+	      /*
+	       * If this is the first point then we must have enough columns.
+	       * If there are enough then we define this to be the number of
+	       * columns that the file must have.
+	       */
 	    } else {
 		  if (cur_columns < minimum_columns) {
 			yyerror("Found %u columns, need at least %u.",
 			        cur_columns, minimum_columns);
-		  } else number_of_columns = cur_columns;
+		  } else {
+			number_of_columns = cur_columns;
+			process_point();
+		  }
 	    }
       }
 
+  /*
+   * Each column is a real value. We only save the columns we care about.
+   */
 columns : REAL
       {
 	    if (table_def->control.info.interp[0] != IVL_IGNORE_COLUMN) {
@@ -103,12 +182,17 @@ columns : REAL
 
 %%
 
+/*
+ * Setup the various variables, then parse the input file and then cleanup
+ * the lexor and the allocated memory.
+ */
 unsigned parse_table_model(FILE *fp, vpiHandle callh, p_table_mod table)
 {
       unsigned rtn = 0;
       assert(table);
       assert(table->fields > 0);
       assert(table->depend > 0);
+	/* Initialize the variables used by the parser.  */
       table_def = table;
       indep_values = table->dims;
       indep_columns = table->fields;
@@ -117,7 +201,9 @@ unsigned parse_table_model(FILE *fp, vpiHandle callh, p_table_mod table)
       values = malloc(sizeof(double)*(indep_values+1));
       assert(values);
       in_file_name = table->file.name;
+	/* Parse the input file. */
       init_tblmod_lexor(fp);
+	/* If there are errors then print a message. */
       if (yyparse()) errors += 1;
       if (errors) {
 	    vpi_printf("ERROR: %s:%u: ", vpi_get_str(vpiFile, callh),
@@ -125,14 +211,15 @@ unsigned parse_table_model(FILE *fp, vpiHandle callh, p_table_mod table)
 	    vpi_printf("Had %u error(s) while reading table file.\n", errors);
 	    rtn = 1;
       }
+	/* Cleanup the lexor and allocated memory. */
       destroy_tblmod_lexor();
       free(values);
       return rtn;
 }
 
 /*
- * Because every parse error is reported after the newline subtract one from
- * the line count.
+ * Currently every parse error is reported after the newline so subtract
+ * one from the line count.
  */
 void yyerror(const char *fmt, ...)
 {