SP_PRNTFRML

PRNTFRML()

  Short:
  ------
  PRNTFRML() Prints a formletter created by formletr()

  Returns:
  --------
  Nothing

  Syntax:
  -------
  PRNTFRML(cForm,[nPageWidth],[nLeftMargin])

  Description:
  ------------
  Prints the form <cForm> from FORMS.DBF with a
  pagewidth of [nPageWidth] and a left margin of [nLeftMargin]

  <cForm> is normally the contents of the template stored in FORMS.DBF
  (previous documentation refered to this parameter as the NAME of the
  form, which is incorrect.

  Examples:
  ---------
  This is used internally by FORMLETR() and FASTFORM().
  Refer to its usage there.

  SELECT 0
  USE FORM
  locate for descript = "MY FORM LETTER" // find letter
  cForm = form->memo_orig      // load contents
  USE
  SELECT MYDBF
  PRNTFRML(cForm,79)


  Source:
  -------
  S_PRNTF.PRG


 

 

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SP_PRNT

PRNT()

  Short:
  ------
  PRNT() Writes a string of a given color at row, column

  Returns:
  --------
  Nothing

  Syntax:
  -------
  PRNT(nRow, nColumn, cString, nColor)

  Description:
  ------------
  <nRow>       row

  <nColumn>    column

  <cString>    string

  <nColor>     color attribute

  Examples:
  ---------
   PRNT(10,10,"Hello there",47)  // +W/G

  Notes:
  -------
  Here mainly for compatibility with older version. Was
  previously a C function.

  Source:
  -------
  S_PRNT.PRG

 

 

Coding Guidelines

Coding Guidelines

( by Greg Holmes )

Language Syntax 
The general rule of thumb is: built-in features in lowercase, and custom-written functions in mixed case. 
When specifying the complete syntax of a language element in documentation, the input items, parameters, and so on are referred to using the following symbols:

 Symbol  Description
< >  Indicates user input item
( )  Indicates function argument list
[ ]  Indicates optional item or list
{ }  Indicates code block or literal array
| |  Indicates code block argument list
–>  Indicates function return value
 Repeated elements if followed by a symbol
Intervening code if followed by a keyword
,  Item list separator
|  Indicates two or more mutually exclusive options
@  Indicates that an item must be passed by reference
*  Indicates a compatibility command or function

For example:

    len(<cString>|<aArray>) --> nLength

Metasymbols provide a place holder for syntax elements, and they describe the expected data types. A metasymbol consists of one or more lowercase data type designators followed by a mixed case description. This is known as Hungarian Notation.

 Designator  Description
a  Array
b  Code block
c  Character expression
d  Date expression
exp  Expression of any type
id  Literal identifier
l  Logical expression
m  Memo field
n  Numeric expression
o  Object
x  Extended expression

In this example, dnLower and dnUpper can be either date or numeric:

    @...get...range <dnLower>, <dnUpper>
Filenames and Aliases 
All filenames, in any context, are in upper case. Filenames follow DOS naming conventions (preferably limited to letters, numbers, and the underscore).

    use CUSTOMER
    nHandle := fopen('DATAFILE.DAT')

When referring to specific file types in documentation, include the period.
e.g. “A program is stored in a text file with a .PRG extension.” 
Alias names follow the same conventions as filenames, but are limited to A-Z, 0-9, and the underscore. If a filename begins with a number or contains unusual characters, an alias must be specified when the file is opened or an error will result. 
Note that CA-Clipper does not natively support Windows 95 long filenames, although third-party libraries are available to add the capability.

Fieldnames 
Fieldnames are all uppercase, and always include the alias of the table. Fieldnames may contain underscores, but should not begin with one (because the underscore is generally used to indicate an internal symbol).

    @ 10, 10 say BANKS->BRANCH
    nAge := CUSTOMER->CUST_AGE
Memory Variables 
Memory variables consist of a lowercase type designator followed by a mixed case description (see Hungarian Notation). Although CA-Clipper only recognizes the first 10 characters as unique, variable names may be longer.

    cString := "Hello World"
    nYearlyAverage := CalcYearAvg()

If you use Hungarian Notation for your memory variable names and include the table alias with fieldnames, there will be no conflict between the two.

Commands, Functions, and Keywords 
All built-in commands, functions, and keywords are lowercase. In documentation, the font should be Courier or a similar font. If fonts are not available, then bold or CAPITALIZE the word for emphasis. 
Never use abbreviations — this practice is not necessary with a compiler, although it was common in the early days of dBase (which was an interpreter). 
There should never be a space between the function name and the opening parenthesis. Also, note that the iif() function should never be spelled if().

    replace CUSTOMER->CUSTNAME with cCustName
    nKey := inkey(0)

When specifying commands that have clauses in documentation, separate the keywords with an ellipsis (...) and do not include the to clause, unless it is followed by the file,print, or screen keywords.

    copy...sdf
    set message...center
    @...say...get
Programmer-Defined Functions & Procedures 
These begin with an uppercase letter, followed by mixed case letters as appropriate.

    ? StripBlanks("Hello there, this will have no spaces.")

Function and procedure names may contain underscores, but should not begin with one (they may conflict with internal functions which often start with an underscore). There should be only one return statement per function or procedure, and it should not be indented.

    function SomeFunc (...)
      .
      . <statements>
      .
    return cResult

The return value of a function is not enclosed in parentheses, although parentheses may be used to clarify a complex expression.

    return nValue
    return (nCode * 47) + nAnswer
Preprocessor Directives 
Preprocessor directives are lowercase and are preceded by the # sign.

    #include 'INKEY.CH'

Optionally, you may use single quotes around header files that come with CA-Clipper and double quotes around your own. This convention is purely voluntary, but it helps to distinguish between the two. For example:

    #include 'INKEY.CH'
    #include "MY_APP.CH"

Manifest constants are uppercase.

    #define ESCAPE   27
    if lastkey() == ESCAPE

Pseudo-function names should also be uppercase.

    #define AREA(length, width)   ((length)*(width))
Declarations 
Local variables are grouped according to functionality, and may be declared on one or more lines. The declarations appear as the first code at the beginning of a function or procedure.

    procedure Main ( )
    local nTop, nLeft, nBottom, nRight
    local cOldScreen, cOldColor, nOldCursor

Variables may be declared one per line and accompanied by a description.

    local nCount        // Number of records found.
    local nTotal        // Sum of dollars.

The description can be omitted if better variable names are chosen.

    local nRecordCount
    local nDollarTotal

Variables can be initialized when they are declared, although it is often clearer (and safer) to initialize them immediately before they are used.

    local nRecordCount:=0
    local nDollarTotal:=0
Logicals 
The .T. and .F. are typed in uppercase.
Operators 
The in-line assignment operator (:=) is used for all assignments, and the exact comparison operator (==) is used for all comparisons.

    lContinue := .T.
    nOfficeTotal := nRegionTotal := 0
    lDuplicate := (CUSTFILE->CUSTNAME == cCustName)
    if nLineCount == 4  ...
    if left(PRODUCT->CODE, 3) == left(cProdCode, 3)  ...

Although the compound assignment operators (+=-=*=, etc.) are convenient, they should not be used if readability suffers.

    // The traditional way to accumulate:
    nTotal := nTotal + INVDETAIL->PRICE
    // A good use of a compound assignment operator:
    nTotal += INVDETAIL->PRICE
    // But what does this do?
    nVal **= 2

The increment (++) and decrement (--) operators are convenient, but can lead to obscure code because of the difference between prefix and postfix usage.

    nRecCount++
    nY := nX-- - --nX        // Huh?
Spacing 
Whenever a list of two or more items is separated by commas, the commas are followed by a space.

    MyFunc(nChoice, 10, 20, .T.)

Spaces may be used between successive parentheses.

    DoCalc( (nItem > nTotal), .F. )
    cNewStr := iif( empty(cStr), cNewStr, cStr + chr(13) )

Spaces should surround all operators for readability.

    nValue := 14 + 5 - (6 / 4)

In declarations, often spaces are not used around the assignment operator. This tends to make searching for the declaration of a variable easier.

    local lResult:=.F., nX:=0

Thus, searching for “nX :=” would find the lines where an assignment is made, while searching for “nX:=” would find the declaration line (such as the local above).

Indentation 
Indenting control structures is one of the easiest techniques, yet it improves the readability the most. 
Indent control structures and the code within functions and procedures 3 spaces.

    procedure SaySomething
       do while .T.
          if nTotal < 50
             ? "Less than 50."
          elseif nTotal > 50
             ? "Greater than 50."
          else
             ? "Equal to 50."
          endif
          ...
       enddo
    return

Case statements in a do…case structure are also indented 3 spaces.

    do case
       case nChoice == 1
          ? "Choice is 1"
       case ...
          ...
       otherwise
          ...
    endcase
Tabs 
Do not use tabs in source code — insert spaces instead. Tabs cause problems when printing or when moving from one editor to another, because of the lack of a standard tab width between editors and printers. Typically, printers expand tabs to 8 spaces which easily causes nested control structures to fall off the right-hand side of the page. Commonly, a source code editing program will insert the appropriate number of spaces when the <TAB> key is hit.
Line Continuation 
When a line of code approaches the 80th column, interrupt the code at an appropriate spot with a semicolon and continue on the next line. Indent the line so that it lines up in a readable manner.

    set filter to CUSTFILE->NAME  == 'John Smith  ';
            .and. CUSTFILE->STATE == 'OR'

To continue a character string, end the first line with a quote and a plus sign and place the remainder on the next line. Try to choose a logical place in the string to break it, either at a punctuation mark or after a space.

    @ 10, 10 say "The lazy brown fox tripped over " + ;
                 "the broken branch."
Quotes 
Use double quotes for text that needs to be translated (will appear on the screen), and single quotes for other strings.

    ? "Hello World!"
    cColor := 'W+/B'
    SelectArea('PROP')

This is a simple but extremely effective technique because translation departments often want to see the messages in context (in the source code), so the different quote types indicate which messages are to be translated and which should be left alone.

Comments 
Comments are structured just like English sentences, with a capital letter at the beginning and a period at the end.

    // Just like a sentence.
    /* This comment is longer. As you
       can see, it takes up two lines */

You may encounter old-style comment indicators if you maintain older (Summer’87 and earlier) code.

    && This is an older-style of comment indicator.
    *  The asterisk is also old.

For in-line comments, use the double slashes.

    use CUSTOMER            // Open the data file.
    goto bottom             // The last record.

Note that the ‘//‘ of in-line comments begins at column 40, if possible. This leaves enough room for a useful comment.

Source :  http://www.ghservices.com/gregh/clipper/guide.htm

C5_#command | #translate

#command | #translate 
 Specify a user-defined command or translation directive

 Syntax

     #command   <matchPattern> => <resultPattern>
     #translate   <matchPattern> => <resultPattern>

 Arguments

     <matchPattern> is the pattern the input text should match.

     <resultPattern> is the text produced if a portion of input text
     matches the <matchPattern>.

     The => symbol between <matchPattern> and <resultPattern> is, along with
     #command or #translate, a literal part of the syntax that must be
     specified in a #command or #translate directive.  The symbol consists of
     an equal sign followed by a greater than symbol with no intervening
     spaces.  Do not confuse the symbol with the >= or the <= comparison
     operators in the Clipper language.

 Description

     #command and #translate are translation directives that define commands
     and pseudofunctions.  Each directive specifies a translation rule.  The
     rule consists of two portions:  a match pattern and a result pattern.
     The match pattern matches a command specified in the program (.prg) file
     and saves portions of the command text (usually command arguments) for
     the result pattern to use.  The result pattern then defines what will be
     written to the result text and how it will be written using the saved
     portions of the matching input text.

     #command and #translate are similar, but differ in the circumstance
     under which their match patterns match input text.  A #command directive
     matches only if the input text is a complete statement, while #translate
     matches input text that is not a complete statement.  #command defines a
     complete command and #translate defines clauses and pseudofunctions that
     may not form a complete statement.  In general, use #command for most
     definitions and #translate for special cases.

     #command and #translate are similar to but more powerful than the
     #define directive.  #define, generally, defines identifiers that control
     conditional compilation and manifest constants for commonly used
     constant values such as INKEY() codes.  Refer to any of the header files
     in the \CLIP53\INCLUDE directory for examples of manifest constants
     defined using #define.

     #command and #translate directives have the same scope as the #define
     directive.  The definition is valid only for the current program (.prg)
     file unless defined in Std.ch or the header specified with the /U option
     on the compiler command line.  If defined elsewhere, the definition is
     valid from the line where it is specified to the end of the program
     file.  Unlike #define, a #translate or #command definition cannot be
     explicitly undefined.  The #undef directive has no effect on a #command
     or #translate definition.

     As the preprocessor encounters each source line preprocessor, it scans
     for definitions in the following order of precedence: #define,
     #translate, and #command.  When there is a match, the substitution is
     made to the result text and the entire line is reprocessed until there
     are no matches for any of the three types of definitions.  #command and
     #translate rules are processed in stack-order (i.e., last in-first out,
     with the most recently specified rule processed first).

     In general, a command definition provides a way to specify an English
     language statement that is, in fact, a complicated expression or
     function call, thereby improving the readability of source code.  You
     can use a command in place of an expression or function call to impose
     order of keywords, required arguments, combinations of arguments that
     must be specified together, and mutually exclusive arguments at compile
     time rather than at runtime.  This can be important since procedures and
     user-defined functions can now be called with any number of arguments,
     forcing any argument checking to occur at runtime.  With command
     definitions, the preprocessor handles some of this.

     All commands in Clipper are defined using the #command directive and
     supplied in the standard header file, Std.ch, located in the
     \CLIP53\INCLUDE directory.  The syntax rules of #command and #translate
     facilitate the processing of all Clipper and dBASE-style commands
     into expressions and function calls.  This provides Clipper
     compatibility, as well as avenues of compatibility with other dialects.

     When defining a command, there are several prerequisites to properly
     specifying the command definition.  Many preprocessor commands require
     more than one #command directive because mutually exclusive clauses
     contain a keyword or argument.  For example, the @...GET command has
     mutually exclusive VALID and RANGE clauses and is defined with a
     different #command rule to implement each clause.

     This also occurs when a result pattern contains different expressions,
     functions, or parameter structures for different clauses specified for
     the same command (e.g., the @...SAY command).  In Std.ch, there is a
     #command rule for @...SAY specified with the PICTURE clause and another
     for @...SAY specified without the PICTURE clause.  Each formulation of
     the command is translated into a different expression.  Because
     directives are processed in stack order, when defining more than one
     rule for a command, place the most general case first, followed by the
     more specific ones.  This ensures that the proper rule will match the
     command specified in the program (.prg) file.

     For more information and a general discussion of commands, refer to the
     "Basic Concepts" chapter in the Programming and Utilities Guide.

 Match Pattern

     The <matchPattern> portion of a translation directive is the pattern the
     input text must match.  A match pattern is made from one or more of the
     following components, which the preprocessor tries to match against
     input text in a specific way:

     .  Literal values are actual characters that appear in the match
        pattern.  These characters must appear in the input text, exactly as
        specified to activate the translation directive.

     .  Words are keywords and valid identifiers that are compared
        according to the dBASE convention (case-insensitive, first four
        letters mandatory, etc.).  The match pattern must start with a Word.

        #xcommand and #xtranslate can recognize keywords of more than four
        significant letters.

     .  Match markers are label and optional symbols delimited by
        angle brackets (<>) that provide a substitute (idMarker) to be used
        in the <resultPattern> and identify the clause for which it is a
        substitute.  Marker names are identifiers and must, therefore, follow
        the Clipper identifier naming conventions.  In short, the name
        must start with an alphabetic or underscore character, which may be
        followed by alphanumeric or underscore characters.

        This table describes all match marker forms:

        Match Markers
        ---------------------------------------------------------------------
        Match Marker             Name
        ---------------------------------------------------------------------
        <idMarker>               Regular match marker
        <idMarker,...>           List match marker
        <idMarker:word list>     Restricted match marker
        <*idMarker*>             Wild match marker
        <(idMarker)>             Extended Expression match marker
        ---------------------------------------------------------------------

        -  Regular match marker: Matches the next legal expression in the
           input text.  The regular match marker, a simple label, is the most
           general and, therefore, the most likely match marker to use for a
           command argument.  Because of its generality, it is used with the
           regular result marker, all of the stringify result markers, and
           the blockify result marker.

        -  List match marker: Matches a comma-separated list of legal
           expressions.  If no input text matches the match marker, the
           specified marker name contains nothing.  You must take care in
           making list specifications because extra commas will cause
           unpredictable and unexpected results.

           The list match marker defines command clauses that have lists as
           arguments.  Typically these are FIELDS clauses or expression lists
           used by database commands.  When there is a match for a list match
           marker, the list is usually written to the result text using either the
           normal or smart stringify result marker.  Often, lists are written
           as literal arrays by enclosing the result marker in curly ({ })
           braces.

        -  Restricted match marker: Matches input text to one of the
           words in a comma-separated list.  If the input text does not match
           at least one of the words, the match fails and the marker name
           contains nothing.

           A restricted match marker is generally used with the logify result
           marker to write a logical value into the result text.  If there is
           a match for the restricted match marker, the corresponding logify
           result marker writes true (.T.) to the result text; otherwise, it
           writes false (.F.).  This is particularly useful when defining
           optional clauses that consist of a command keyword with no
           accompanying argument.  Std.ch implements the REST clause of
           database commands using this form.

        -  Wild match marker: Matches any input text from the current
           position to the end of a statement.  Wild match markers generally
           match input that may not be a legal expression, such as #command
           NOTE <*x*> in Std.ch, gather the input text to the end of the
           statement, and write it to the result text using one of the
           stringify result markers.

        -  Extended expression match marker: Matches a regular or
           extended expression, including a file name or path specification.
           It is used with the smart stringify result marker to ensure that
           extended expressions will not get stringified, while normal,
           unquoted string file specifications will.

     .  Optional match clauses are portions of the match pattern
        enclosed in square brackets ([ ]).  They specify a portion of the
        match pattern that may be absent from the input text.  An optional
        clause may contain any of the components allowed within a
        <matchPattern>, including other optional clauses.

        Optional match clauses may appear anywhere and in any order in the
        match pattern and still match input text.  Each match clause may
        appear only once in the input text.  There are two types of optional
        match clauses: one is a keyword followed by match marker, and the
        other is a keyword by itself.  These two types of optional match
        clauses can match all of the traditional command clauses typical of
        the Clipper command set.

        Optional match clauses are defined with a regular or list match
        marker to match input text if the clause consists of an argument or a
        keyword followed by an argument (see the INDEX clause of the USE
        command in Std.ch).  If the optional match clause consists of a
        keyword by itself, it is matched with a restricted match marker (see
        the EXCLUSIVE or SHARED clause of the USE command in Std.ch).

        In any match pattern, you may not specify adjacent optional match
        clauses consisting solely of match markers, without generating a
        compiler error.  You may repeat an optional clause any number of
        times in the input text, as long as it is not adjacent to any other
        optional clause.  To write a repeated match clause to the result
        text, use repeating result clauses in the <resultPattern> definition.

 Result Pattern

     The <resultPattern> portion of a translation directive is the text the
     preprocessor will produce if a piece of input text matches the
     <matchPattern>.  <resultPattern> is made from one or more of the
     following components:

     .  Literal tokens are actual characters that are written directly
        to the result text.

     .  Words are Clipper keywords and identifiers that are written
        directly to the result text.

     .  Result markers:  refer directly to a match marker name.  Input
        text matched by the match marker is written to the result text via
        the result marker.

        This table lists the Result marker forms:

        Result Markers
        ---------------------------------------------------------------------
        Result Marker     Name
        ---------------------------------------------------------------------
        <idMarker>        Regular result marker
        #<idMarker>       Dumb stringify result marker
        <"idMarker">      Normal stringify result marker
        <(idMarker)>      Smart stringify result marker
        <{idMarker}>      Blockify result marker
        <.idMarker.>      Logify result marker
        ---------------------------------------------------------------------

        -  Regular result marker:  Writes the matched input text to the
           result text, or nothing if no input text is matched.  Use this,
           the most general result marker, unless you have special
           requirements.  You can use it with any of the match markers, but
           it almost always is used with the regular match marker.

        -  Dumb stringify result marker:  Stringifies the matched input
           text and writes it to the result text.  If no input text is
           matched, it writes a null string ("").  If the matched input text
           is a list matched by a list match marker, this result marker
           stringifies the entire list and writes it to the result text.

           This result marker writes output to result text where a string is
           always required.  This is generally the case for commands where a
           command or clause argument is specified as a literal value but the
           result text must always be written as a string even if the
           argument is not specified.

        -  Normal stringify result marker:  Stringifies the matched input
           text and writes it to the result text.  If no input text is
           matched, it writes nothing to the result text.  If the matched
           input text is a list matched by a list match marker, this result
           marker stringifies each element in the list and writes it to the
           result text.

           The normal stringify result marker is most often used with the
           blockify result marker to compile an expression while saving a
           text image of the expression (See the SET FILTER condition and the
           INDEX key expression in Std.ch).

        -  Smart stringify result marker:  Stringifies matched input text
           only if source text is enclosed in parentheses.  If no input text
           matched, it writes nothing to the result text.  If the matched
           input text is a list matched by a list match marker, this result
           marker stringifies each element in the list (using the same
           stringify rule) and writes it to the result text.

           The smart stringify result marker is designed specifically to
           support extended expressions for commands other than SETs with
           <xlToggle> arguments.  Extended expressions are command syntax
           elements that can be specified as literal text or as an expression
           if enclosed in parentheses.  The <xcDatabase> argument of the USE
           command is a typical example.  For instance, if the matched input
           for the <xcDatabase> argument is the word Customer, it is written
           to the result text as the string "Customer," but the expression
           (cPath + cDatafile) would be written to the result text unchanged
           (i.e., without quotes).

        -  Blockify result marker: Writes matched input text as a code
           block without any arguments to the result text.  For example, the
           input text x + 3 would be written to the result text as {|| x +
           3}.  If no input text is matched, it writes nothing to the result
           text.  If the matched input text is a list matched by a list match
           marker, this result marker blockifies each element in the list.

           The blockify result marker used with the regular and list match
           markers matches various kinds of expressions and writes them as
           code blocks to the result text.  Remember that a code block is a
           piece of compiled code to execute sometime later.  This is
           important when defining commands that evaluate expressions more
           than once per invocation.  When defining a command, you can use
           code blocks to pass an expression to a function and procedure as
           data rather than as the result of an evaluation.  This allows the
           target routine to evaluate the expression whenever necessary.

           In Std.ch, the blockify result marker defines database commands
           where an expression is evaluated for each record.  Commonly, these
           are field or expression lists, FOR and WHILE conditions, or key
           expressions for commands that perform actions based on key values.

        -  Logify result marker: Writes true (.T.) to the result text if
           any input text is matched; otherwise, it writes false (.F.) to the
           result text.  This result marker does not write the input text
           itself to the result text.

           The logify result marker is generally used with the restricted match
           marker to write true (.T.) to the result text if an optional
           clause is specified with no argument; otherwise, it writes false
           (.F.).  In Std.ch, this formulation defines the EXCLUSIVE and
           SHARED clauses of the USE command.

     .  Repeating result clauses are portions of the <resultPattern>
        enclosed by square brackets ([ ]).  The text within a repeating
        clause is written to the result text as many times as it has input
        text for any or all result markers within the clause.  If there is no
        matching input text, the repeating clause is not written to the
        result text.  Repeating clauses, however, cannot be nested.  If you
        need to nest repeating clauses, you probably need an additional
        #command rule for the current command.

        Repeating clauses are the result pattern part of the #command
        facility that create optional clauses which have arguments.  You can
        match input text with any match marker other than the restricted
        match marker and write to the result text with any of the
        corresponding result markers.  Typical examples of this facility are
        the definitions for the STORE and REPLACE commands in Std.ch.

 Notes

     .  Less than operator: If you specify the less than operator (<)
        in the <resultPattern> expression, you must precede it with the
        escape character (\).

     .  Multistatement lines: You can specify more than one statement
        as a part of the result pattern by separating each statement with a
        semicolon.  If you specify adjacent statements on two separate lines,
        the first statement must be followed by two semicolons.

 Examples

     These examples encompass many of the basic techniques you can use when
     defining commands with the #command and #translate directives.  In
     general, these examples are based on standard commands defined in
     Std.ch.  Note, however, the functions specified in the example result
     patterns are not the actual functions found in Std.ch, but fictitious
     functions specified for illustration only.

     .  This example defines the @...BOX command using regular match
        markers with regular result markers:

        #command  @ <top>, <left>, <bottom>, <right> BOX ;
              <boxstring>;
        =>;
              CmdBox( <top>, <left>, <bottom>, ;
              <right>,<boxstring> )

     .  This example uses a list match marker with a regular result
        marker to define the ? command:

        #command ? [<list,...>] => QOUT(<list>)

     .  This example uses a restricted match marker with a logify
        result marker to implement an optional clause for a command
        definition.  In this example, if the ADDITIVE clause is specified,
        the logify result marker writes true (.T.) to the result text;
        otherwise, it writes false (.F.):

        #command RESTORE FROM <file> [<add: ADDITIVE>];
        =>;
              CmdRestore( <(file)>, <.add.> )

     .  This example uses a list match marker with a smart stringify
        result marker to write to the result text the list of fields
        specified as the argument of a FIELDS clause.  In this example, the
        field list is written as an array with each field name as an element
        of the array:

        #command COPY TO <file> [FIELDS <fields,...>];
        =>;
              CmdCopyAll( <(file)>, { <(fields)> } )

     .  These examples use the wild match marker to define a command
        that writes nothing to the result text.  Do this when attempting to
        compile unmodified code developed in another dialect:

        #command SET ECHO <*text*>    =>
        #command SET TALK <*text*>    =>

     .  These examples use wild match markers with dumb stringify
        result markers to match command arguments specified as literals, then
        write them to the result text as strings in all cases:

        #command SET PATH TO <*path*>  =>  ;
           SET( _SET_PATH, #<path> )
        #command SET COLOR TO <*spec*> =>  SETCOLOR( #<spec> )

     .  These examples use a normal result marker with the blockify
        result marker to both compile an expression and save the text version
        of it for later use:

        #command SET FILTER TO <xpr>;
        =>;
              CmdSetFilter( <{xpr}>, <"xpr"> )

        #command INDEX ON <key> TO <file>;
        =>;
              CmdCreateIndex( <(file)>, <"key">, <{key}> )

     .  This example demonstrates how the smart stringify result
        marker implements a portion of the USE command for those arguments
        that can be specified as extended expressions:

        #command USE <db> [ALIAS <a>];
        =>;
              CmdOpenDbf( <(db)>, <(a)> )

     .  This example illustrates the importance of the blockify result
        marker for defining a database command.  Here, the FOR and WHILE
        conditions matched in the input text are written to the result text
        as code blocks:

        #command COUNT [TO <var>];
              [FOR <for>] [WHILE <while>];
              [NEXT <next>] [RECORD <rec>] [<rest:REST>] [ALL];
        =>;
              <var> := 0,;
              DBEVAL( {|| <var>++}, <{for}>, <{while}>,;
                 <next>, <rec>, <.rest.> )

     .  In this example the USE command again demonstrates the types
        of optional clauses with keywords in the match pattern.  one clause
        is a keyword followed by a command argument, and the second is solely
        a keyword:

        #command USE <db> [<new: NEW>] [ALIAS <a>] ;
              [INDEX <index,...>][<ex: EXCLUSIVE>] ;
              [<sh: SHARED>] [<ro: READONLY>];
        =>;
              CmdOpenDbf(<(db)>, <(a)>, <.new.>,;
                 IF(<.sh.> .OR. <.ex.>, !<.ex.>, NIL),;
                    <.ro.>, {<(index)>})

     .  This example uses the STORE command definition to illustrate
        the relationship between an optional match clause and a repeating
        result clause:

        #command STORE <value> TO <var1> [, <varN> ];
        =>;
              <var1> := [ <varN> := ] <value>

     .  This example uses #translate to define a pseudofunction:

        #translate AllTrim(<cString>) => LTRIM(RTRIM(<cString>))

See Also: #define #xcommand


			

C5 Directives

#command        Specify a user-defined command or translation directive
#define         Define a manifest constant or pseudofunction
#error          Generate a compiler error and display a message
#ifdef          Compile a section of code if an identifier is defined
#ifndef         Compile a section of code if an identifier is undefined
#include        Include a file into the current source file
#stdout         Send literal text to the standard output device
#translate      Specify a user-defined command or translation directive
#undef          Remove a #define macro definition 
#xcommand       Specify a user-defined command or translation directive
#xtranslate     Specify a user-defined command or translation directive

Using code blocks, again

Using code blocks again (.pdf)

Array and GET tricks

Array and GET tricks