Document PROC parameters, use parameters in pi.bas sample.

Author: dmsc

manual.md

@@ -40,7 +40,8 @@ Currently, FastBasic supports:
   255 characters.
 - Arrays of "word", "byte", floating
   point and strings.
-- User defined procedures.
+- User defined procedures, with integer
+  parameters.
 - Compilation to binary loadable files.
 - Available as a full version `FB.COM`,
   as a smaller integer-only `FBI.COM`
@@ -1044,12 +1045,16 @@ Control Statements
 
 
 **Calls A Subroutine**  
-**EXEC _name_ / EXE.**
+**EXEC _name_ _num1_, ... / EXE.**
 
-  Calls the subroutine _name_. Note
-  that the subroutine must be defined
-  with PROC, but can be defined before
-  or after the call.
+  Calls the subroutine _name_, with the
+  optional parameters _num1_ and so on,
+  separated by commas.
+
+  Note that the subroutine must be
+  defined with PROC with the same number
+  of parameters, but can be defined
+  before or after the call.
 
 
 **Exits From Loop Or PROC**  
@@ -1165,13 +1170,26 @@ Control Statements
 
 
 **Define A Subroutine.**  
-**PROC _name_ / PR.**  
+**PROC _name_ _var1_ .../ PR.**  
 **ENDPROC / ENDP.**
 
   PROC statement starts the definition
   of a subroutine that can be called
   via EXEC.
 
+  You can pass a list of integer
+  variables separated by spaces after
+  the PROC name to specify a number of
+  parameters, the variables will be set
+  to the values passed by the EXEC call.
+  Those variable names are always
+  global, so the values set are seen
+  outside the PROC.
+
+  The number of parameters in the PROC
+  definition and in all the EXEC calls
+  must be the same.
+
   Note that if the PROC statement is
   encountered while executing
   surrounding code, the full subroutine

samples/int/pi.bas

@@ -12,8 +12,6 @@
 DIM P(130), T(130) BYTE, SV(130) BYTE
 
 ' Arguments to procedures bellow
-MULT=0
-DIVI=0
 ZERO=0
 
 ' Precision in digit pairs
@@ -30,15 +28,15 @@ NEXT
 
 ' Calculate ATAN(1/5), positive:
 PRINT "A(1/5):";
-AS=1 : AT=5   : EXEC ARCTAN_SMALL
+EXEC ARCTAN_SMALL 1, 5
 PRINT
 
 ' Multiply by 4
 EXEC MUL4
 
 ' Calculate ATAN(1/239), negative:
 PRINT "A(1/239):";
-AS=0 : AT=239 : EXEC ARCTAN
+EXEC ARCTAN 0, 239
 PRINT
 
 ' Multiply all by 4
@@ -75,24 +73,21 @@ ENDPROC
 ' Calculate ATAN(1/AT), adding the
 ' result to P()
 '
-PROC ARCTAN
+PROC ARCTAN AS AT
  T(0)=1
  ZERO=0
- DIVI=AT
- EXEC DIV
+ EXEC DIV AT
  EXEC SAVE_T
  N=1
  REPEAT
   EXEC ADDSUB
   EXEC RESTORE_T
-  DIVI=AT
-  EXEC DIV
-  EXEC DIV
+  EXEC DIV AT
+  EXEC DIV AT
   EXEC SAVE_T
   EXEC CHKZERO
   N=N+2
-  DIVI=N
-  EXEC DIV
+  EXEC DIV N
   PRINT ".";
  UNTIL ZERO<0
 ENDPROC
@@ -102,24 +97,21 @@ ENDPROC
 ' number (so that AT*AT*100 < 32768),
 ' adding the result to P().
 '
-PROC ARCTAN_SMALL
+PROC ARCTAN_SMALL AS AT
  T(0)=1
  ZERO=0
- DIVI=AT
- EXEC DIV
+ EXEC DIV AT
  EXEC SAVE_T
  N=1
  AT=AT*AT
  REPEAT
   EXEC ADDSUB
   EXEC RESTORE_T
   N=N+2
-  DIVI=AT
-  EXEC DIV
+  EXEC DIV AT
   EXEC CHKZERO
   EXEC SAVE_T
-  DIVI=N
-  EXEC DIV
+  EXEC DIV N
   PRINT ".";
  UNTIL ZERO<0
 ENDPROC
@@ -204,10 +196,10 @@ ENDPROC
 ' Multiplies T() by the small number
 ' MULTI, only works if MULTI*100<32768
 '
-PROC MUL
+PROC MUL MULTI
  C=0
  FOR I=Q TO 0 STEP -1
-  B = T(I) * MULT + C
+  B = T(I) * MULTI + C
   T(I) = B MOD 100
   C = B / 100
  NEXT
@@ -217,7 +209,7 @@ ENDPROC
 ' Divides T() by the small number DIVI,
 ' only works if DIVI*100<32768
 '
-PROC DIV
+PROC DIV DIVI
  C=0
  FOR I=ZERO TO Q
   B = 100 * C + T(I)