Add Tab_Stop variable.

For #314

3 files changed, 12 insertions, 4 deletions

diff --git a/src/files_map.adb b/src/files_map.adb
index 3cb7e0594..66b3a1087 100644
--- a/src/files_map.adb
+++ b/src/files_map.adb
@@ -261,7 +261,8 @@ package body Files_Map is
    --  Convert a physical column to a logical column.
    --  A physical column is the offset in byte from the first byte of the line.
    --  A logical column is the position of the character when displayed.
-   --  A HT (tabulation) moves the cursor to the next position multiple of 8.
+   --  A HT (tabulation) moves the cursor to the next position multiple of the
+   --  tab stop.
    --  The first character is at position 1 and at offset 0.
    procedure Coord_To_Position (File : Source_File_Entry;
                                 Line_Pos : Source_Ptr;
@@ -278,7 +279,7 @@ package body Files_Map is
       else
          for I in Line_Pos .. Line_Pos + Source_Ptr (Offset) - 1 loop
             if Source_File.Source (I) = ASCII.HT then
-               Res := Res + 8 - Res mod 8;
+               Res := Res + Tab_Stop - Res mod Tab_Stop;
             else
                Res := Res + 1;
             end if;
diff --git a/src/files_map.ads b/src/files_map.ads
index d06805948..55933ebc3 100644
--- a/src/files_map.ads
+++ b/src/files_map.ads
@@ -22,6 +22,13 @@ with Nodes;
 
 package Files_Map is
 
+   --  Range for Tab_Stop.
+   subtype Tab_Stop_Range is Natural range 1 .. 120;
+
+   --  Tab width: a tab character jumps to the next column that is one plus a
+   --  multiple of this witdh (if columns are numbered from 1).
+   Tab_Stop : Tab_Stop_Range := 8;
+
    --  Create the path from DIRECTORY and NAME:
    --  If NAME is an absolute pathname, then return NAME.
    --  Otherwise, return the concatenation of DIRECTORY and NAME.
diff --git a/src/ghdldrv/ghdlprint.adb b/src/ghdldrv/ghdlprint.adb
index 53df620ae..9aac16824 100644
--- a/src/ghdldrv/ghdlprint.adb
+++ b/src/ghdldrv/ghdlprint.adb
@@ -146,8 +146,8 @@ package body Ghdlprint is
             C := Buf (P);
             if C = HT then
                --  Expand TABS.
-               N_Col := Col + 8;
-               N_Col := N_Col - N_Col mod 8;
+               N_Col := Col + Tab_Stop;
+               N_Col := N_Col - N_Col mod Tab_Stop;
                while Col < N_Col loop
                   Put (' ');
                   Col := Col + 1;