Passing parameters to functions (post blocks) - Is it actually possible?

[Sparky961]

When I was browsing through some resources, I came across an example post in one of the CHook projects. I was surprised to see that it seemed to be passing parameters to post blocks when I haven't seen any documentation on this.

Does anyone know how exactly this is intended to work with respect to declaring variables, naming, etc? Any chance a value can also be returned from a postblock?

 

Here's the contents of the file "MPDraw_Ex.mcpost":

[POST_VERSION] #DO NOT MOVE OR ALTER THIS LINE# V20.00 P4 E1 W20.00 T1517249798 M20.00 I0 O0

#region User Settings
#<UserSettings>

MPDrawDebugOutput : no$  # Output arguments passed to the MPDraw.dll
geometryLevel : 101      # Level to create/remove geometry

#</UserSettings>
#endregion End User Settings

#region Post Settings

rotary_type$ : 5

#endregion End Post Settings

#region Format Statments

fs2 1   0.8 0.7
fs2 2   1 0 1 0

#endregion End Format Statments

#region Draw Geometry

#region Geometry Variable Initializations

#region Enumerators

# Geometry type
DELETE@    : 0
LINE@      : 1
ARC@       : 2

# View number
TOP@       : 1
FRONT@     : 2
BACK@      : 3
BOTTOM@    : 4
RIGHT@     : 5
LEFT@      : 6
ISOMETRIC@ : 7

#endregion End Enumerators

#region Numeric Variable Initializations

# Return value for dll function
dllReturn : 0

# Line start and end point variables
lineStartX : 0
lineStartY : 0
lineStartZ : 0
lineEndX   : 0
lineEndY   : 0
lineEndZ   : 0

# Arc variables
arcView        : 0
arcCenterX     : 0
arcCenterY     : 0
arcCenterZ     : 0
arcRadius      : 0
arcStartAngle  : 0
arcEndAngle    : 0

# Line start and end point variables formatted for output to MPDraw.dll
fmt "" 1 sx
fmt "" 1 sy
fmt "" 1 sz
fmt "" 1 ex
fmt "" 1 ey
fmt "" 1 ez

# Arc variables formatted for output to MPDraw.dll
fmt "" 2 arcview
fmt "" 1 acx
fmt "" 1 acy
fmt "" 1 acz
fmt "" 1 ar
fmt "" 1 as
fmt "" 1 ae

# level and geometry type variables formatted for output to MPDraw.dll
fmt "" 2 level
fmt "" 2 geometryType

#endregion End Numeric Variable Initializations

#region String Variable Initializations

ssq    : "'" # Single quote character
sdq    : '"' # Double quote character
sspace : " " # Space character

sMPDrawDLL    = "MPDraw.dll"  # Constant string containg 'MPDraw.dll'
sdeleteData   = "0"           # Constant string to hold the delete data
slineData     : ""            # String to hold the line data
sarcData      : ""            # String to hold the arc data

sMPDeleteArgs     : "" # String to pass the delete arguments to MPDraw.dll
sMPLineArgs       : "" # String to pass the line arguments to MPDraw.dll
sMPArcArgs        : "" # String to pass the arc arguments to MPDraw.dll

#endregion End String Variable Initializations

#endregion End Geometry Variable Initializations

#region Geometry Post Blocks

# Remove all geometry from a specified level
pDeleteGeometry(level)
      # Set the geometryType
      geometryType = DELETE@

      # Construct the delete argument string(sdeleteData, level, geometryType)
      sMPDeleteArgs = ssq + sdq + sdeleteData + sdq + sspace + sdq + drs_str(2, level) + sdq + sspace + sdq + drs_str(2, geometryType) + sdq + ssq

      # Call the MPDraw.dll passing it the constructed argument string
      dllReturn = dll(sMPDrawDLL, sMPDeleteArgs)

      # If MPDrawDebugOutput = yes$, write the delete arguments to the NC file
      if MPDrawDebugOutput, " Delete Arguments : ", *sMPDeleteArgs, e$

# Draw a line on a specified level
pDrawLine(sx, sy, sz, ex, ey, ez, level)
      # Set the geometryType
      geometryType = LINE@

      # Convert the line data to a string
      slineData = drs_str(2, sx) + sspace + drs_str(2, sy) + sspace + drs_str(2, sz) + sspace + drs_str(2, ex) + sspace + drs_str(2, ey) + sspace + drs_str(2, ez)

      # Construct the line argument string(slineData, level, geometryType)
      sMPLineArgs = ssq + sdq + slineData + sdq + sspace + sdq + drs_str(2, level) + sdq + sspace + sdq + drs_str(2, geometryType) + sdq + ssq

      # Call the MPDraw.dll passing it the constructed argument string
      dllReturn = dll(sMPDrawDLL, sMPLineArgs)

      # If MPDrawDebugOutput = yes$, write the line arguments to the NC file
      if MPDrawDebugOutput, " Line Arguments   : ", *sMPLineArgs, e$

# Draw an arc on a specified level
pDrawArc(arcview, acx, acy, acz, ar, as, ae, level)
      # Set the geometryType
      geometryType = ARC@

      # Convert the arc data to a string
      sarcData = drs_str(2, arcview) + sspace + drs_str(2, acx) + sspace + drs_str(2, acy) + sspace + drs_str(2, acz) + sspace + drs_str(2, ar) + sspace + drs_str(2, as) + sspace + drs_str(2, ae)

      # Construct the arc argument string(sarcData, level, geometryType)
      sMPArcArgs = ssq + sdq + sarcData + sdq + sspace + sdq + drs_str(2, level) + sdq + sspace + sdq + drs_str(2, geometryType) + sdq + ssq

      # Call the MPDraw.dll passing it the constructed argument string
      dllReturn = dll(sMPDrawDLL, sMPArcArgs)

      # If MPDrawDebugOutput = yes$, write the arc arguments to the NC file
      if MPDrawDebugOutput, " Arc Arguments    : ", *sMPArcArgs, e$

#endregion End Geometry Post Blocks

#endregion End Draw Geometry

#region System Post Blocks

pheader$  #  pheader$ - in this example this post block runs first
      #  Remove all geometry on a specified level
      pDeleteGeometry(geometryLevel)

psof$  #  psof$ - in this example this post block runs second
      lineStartX = vequ(x$)
      lineEndX = vequ(m7$)
      #  Create a line on a specified level starting from the current x$,y$,z$ and extenting to the tool the toolplane Z
      pDrawLine(lineStartX, lineStartY, lineStartZ, lineEndX, lineEndY, lineEndZ, geometryLevel)

peof$  #  peof$ - in this example this post block runs last
      arcView = TOP@
      arcCenterX = 0
      arcCenterY = 0
      arcCenterZ = 1
      arcRadius = .5
      arcStartAngle = 0
      arcEndAngle = 360
      #  Create an arc on a specified level using the values above
      pDrawArc(arcView, arcCenterX, arcCenterY, arcCenterZ, arcRadius, arcStartAngle, arcEndAngle, geometryLevel)

#endregion End System Post Blocks