Improve code readability

diff --git a/Math/Truth table calculator/truth.bas b/Math/Truth table calculator/truth.bas
index 6ecf0f8..204c161 100755 (executable)
--- a/Math/Truth table calculator/truth.bas
+++ b/Math/Truth table calculator/truth.bas
@@ -23,7 +23,7 @@
 '   AND ( Keyboard shortcut: 4 )\r
 '   NOT ( Keyboard shortcut: 5 )\r
 \r
-DECLARE SUB rmslg (x1!, x3!, l!)\r
+DECLARE SUB removeRedundancies (startIndex!, endIndex!, removalCount!)\r
 DECLARE SUB getP (a!, b!)\r
 DECLARE SUB movM (x1!, n!)\r
 DECLARE SUB lihts (x1, x2, l)\r
@@ -176,14 +176,14 @@ m = c - x1 + 1
 END SUB\r
 \r
 SUB lihts (x1, x2, l)\r
-' Removes redundant parentheses from the logical expression\r
-rmslg x1, x2, l1\r
-l = l1\r
-'BEEP\r
-prnp = prnp + 1\r
-FOR a = x1 TO x2 - l\r
-    prn a, 0, 13, 1, CHR$(tehe(a))\r
-NEXT a\r
+    ' Removes redundant parentheses from the logical expression and marks how many were removed\r
+    removeRedundancies x1, x2, l1\r
+    l = l1\r
+    'BEEP\r
+    prnp = prnp + 1\r
+    FOR a = x1 TO x2 - l\r
+        prn a, 0, 13, 1, CHR$(tehe(a))\r
+    NEXT a\r
 END SUB\r
 \r
 SUB mov (x1, n)\r
@@ -246,62 +246,74 @@ a$ = INPUT$(1)
 END SUB\r
 \r
 SUB prn (x, y, c, c1, a$)\r
-' Prints characters to the screen in a specific location and color\r
-x1 = x * 8\r
-y1 = (y + prnp) * 8\r
-\r
-FOR b = 1 TO LEN(a$)\r
-    LINE (x1, y1)-(x1 + 7, y1 + 7), c1, BF\r
-    d = ASC(RIGHT$(LEFT$(a$, b), 1))\r
-    IF d > 122 THEN GOTO 22\r
-    FOR y2 = 0 TO 7\r
-        FOR x2 = 0 TO 7\r
-            c2 = font(x2, y2, d)\r
-            IF c2 > 0 THEN PSET (x1 + x2, y1 + y2), c\r
-        NEXT x2\r
-    NEXT y2\r
-    22\r
-    x1 = x1 + 8\r
-NEXT b\r
+    ' Prints characters to the screen at location (x,y) with color c, background c1\r
+    x1 = x * 8\r
+    y1 = (y + prnp) * 8\r
+\r
+    FOR b = 1 TO LEN(a$)\r
+        LINE (x1, y1)-(x1 + 7, y1 + 7), c1, BF\r
+        d = ASC(RIGHT$(LEFT$(a$, b), 1))\r
+        IF d > 122 THEN GOTO 22\r
+        FOR y2 = 0 TO 7\r
+            FOR x2 = 0 TO 7\r
+                c2 = font(x2, y2, d)\r
+                IF c2 > 0 THEN PSET (x1 + x2, y1 + y2), c\r
+            NEXT x2\r
+        NEXT y2\r
+22      x1 = x1 + 8\r
+    NEXT b\r
 \r
 END SUB\r
 \r
-SUB rmslg (x1, x3, l)\r
-' Removes redundant parentheses from the logical expression\r
-x2 = x3\r
-l2 = 0\r
+SUB removeRedundancies (startIndex, endIndex, removalCount)\r
+    ' This procedure scans for parentheses that can be safely removed\r
+    ' without changing the logic of the expression, then removes them.\r
 \r
-a = x1\r
-26\r
-IF tehe(a) = 40 THEN\r
-    IF a = x1 THEN p1 = 100 ELSE getP tehe(a - 1), p1\r
-    c = a\r
-    d = 1\r
-    p2 = 0\r
-    25\r
-    c = c + 1\r
-    IF tehe(c) = 40 THEN d = d + 1\r
-    IF tehe(c) = 41 THEN d = d - 1\r
-    IF d = 1 THEN\r
-        IF (tehe(c) > 0) AND (tehe(c) <= 5) THEN\r
-            getP tehe(c), b\r
-            IF b > p2 THEN p2 = b\r
+    DIM currentEnd, parenthesesCount\r
+    currentEnd = endIndex\r
+    parenthesesCount = 0\r
+\r
+    a = startIndex\r
+26  IF tehe(a) = 40 THEN\r
+        ' We found an opening parenthesis. Now let's see if it can be removed.\r
+        IF a = startIndex THEN p1 = 100 ELSE getP tehe(a - 1), p1\r
+\r
+        c = a\r
+        d = 1\r
+        p2 = 0\r
+\r
+25      c = c + 1\r
+        IF tehe(c) = 40 THEN d = d + 1\r
+        IF tehe(c) = 41 THEN d = d - 1\r
+\r
+        ' Once d returns to 1, we are back to one level of parentheses,\r
+        ' meaning we can check operator priority inside.\r
+        IF d = 1 THEN\r
+            IF (tehe(c) > 0) AND (tehe(c) <= 5) THEN\r
+                getP tehe(c), b\r
+                IF b > p2 THEN p2 = b\r
+            END IF\r
+        END IF\r
+\r
+        IF d > 0 THEN GOTO 25\r
+\r
+        IF c + 1 > currentEnd THEN p3 = 100 ELSE getP tehe(c + 1), p3\r
+\r
+        ' If the operator outside is higher priority than what's inside,\r
+        ' we can safely remove the parentheses.\r
+        IF (p1 > p2) AND (p3 >= p2) THEN\r
+            movM c, 1\r
+            movM a, 1\r
+            parenthesesCount = parenthesesCount + 2\r
+            currentEnd = currentEnd - 2\r
+            a = a - 1\r
         END IF\r
     END IF\r
-    IF d > 0 THEN GOTO 25\r
-    IF c + 1 > x2 THEN p3 = 100 ELSE getP tehe(c + 1), p3\r
-\r
-    IF (p1 > p2) AND (p3 >= p2) THEN\r
-        movM c, 1\r
-        movM a, 1\r
-        l2 = l2 + 2\r
-        x2 = x2 - 2\r
-        a = a - 1\r
-    END IF\r
-END IF\r
-a = a + 1\r
-IF a <= x2 THEN GOTO 26\r
-l = l2\r
+\r
+    a = a + 1\r
+    IF a <= currentEnd THEN GOTO 26\r
+\r
+    removalCount = parenthesesCount\r
 END SUB\r
 \r
 SUB sist\r
@@ -504,14 +516,16 @@ FOR a = x1 TO x2
 NEXT a\r
 \r
 GOTO 9\r
+\r
 mkneg:\r
-FOR c = 1 TO tehl\r
-    d = opr(oprm, c)\r
-    IF d = ASC("t") THEN d = ASC("v") ELSE d = ASC("t")\r
-    prn xloc(ngx), c, 4, 0, CHR$(d)\r
-    opr(oprm, c) = d\r
-NEXT c\r
-ng = 0\r
+    ' NOT operation (negation) is applied to the current operand\r
+    FOR c = 1 TO tehl\r
+        d = opr(oprm, c)\r
+        IF d = ASC("t") THEN d = ASC("v") ELSE d = ASC("t")\r
+        prn xloc(ngx), c, 4, 0, CHR$(d)\r
+        opr(oprm, c) = d\r
+    NEXT c\r
+    ng = 0\r
 RETURN\r
 9\r
 \r

diff --git a/index.org b/index.org
index 2902d06..55dd852 100644 (file)
--- a/index.org
+++ b/index.org
@@ -236,8 +236,8 @@ auto-apply it, here is how you can set it manually:
 1. Edit file:
   : ~/.dosbox/dosbox-<version>.conf
 
-2. Modify *keyboardlayout* field as follows
-  : keyboardlayout=dv103
+2. Disable scancodes usage:
+   : usescancodes=false
 
 3. Save the changes and restart DOSBox for the configuration to take
    effect.
@@ -257,6 +257,9 @@ appear small. To make it bigger:
 3. Save the changes and restart DOSBox for the configuration to take
    effect.
 
+4. If scaling did not work, set output to opengl:
+   : output=opengl
+
 *** Exit mouse capture
 
 DOSBox detects when a game uses mouse control. When you click on the