![]() ![]() The following example creates two options and adds them to the root command. The innermost subcommand in this example can be invoked like this: myapp sub1 sub1aĪ command handler method typically has parameters, and the values can come from command-line options. Var sub1aCommand = new Command("sub1a", "Second level subcommand") Var sub1Command = new Command("sub1", "First-level subcommand") You can add subcommands as shown in the following example: var rootCommand = new RootCommand() Var rootCommand = new RootCommand("Sample command-line app") Ĭommands can have child commands, known as subcommands or verbs, and they can nest as many levels as you need. ![]() The simplest case for invoking your code, if you have an app with no subcommands, options, or arguments, would look like this: using System.CommandLine Define a root commandĮvery command-line app has a root command, which refers to the executable file itself. ![]() To build a complete application that illustrates these techniques, see the tutorial Get started with System.CommandLine.įor guidance on how to design a command-line app's commands, options, and arguments, see Design guidance. This article explains how to define commands, options, and arguments in command-line apps that are built with the System.CommandLine library. ![]() Microsoft makes no warranties, express or implied, with respect to the information provided here. Some information relates to prerelease product that may be substantially modified before it's released. This can be fixed with the following function:ġ0 DEF FN FR(X) = FRE(0)-65536*(FRE(0)<0)Īs a side-effect FRE() is called twice which could result in doubling the delay imposed by the Garbage is currently in PREVIEW, and this documentation is for version 2.0 beta 4. The function FRE is famously know for the bug which returns negative values if the result exceeds 32767. Several mathematical functions and commands are summarized.Ģ0 DEF FN F1(X) = ( LEN(A$)/ VAL(A$) ) * PEEK(53280)Ĥ0 DEF FN F2(X) = INT( ABS( FN F1(X)* 1E+8) / ASC(A$) )ĭouble PEEK (get a pointer value from a memory location), also known as function DEEK() in other BASIC dialects:Ģ0 PRINT "BASIC PROGRAM LENGTH" FN DP(49) - FN DP(43) The following example gives a glimpse what is possible with functions defined by DEF. In Line 30 the newly defined logarithm function LO10 is executed. This example defines the calculation of the logarithm of 10 in command line 10. In the next example, one numeric expression must be delivered, but is not accounted for afterwards, because only the variables A and B are calculated. The placeholder variable name is expected to be a simple numeric variable name otherwise, like for a string variable name, it leads to ?TYPE MISMATCH ERROR.įor a start a rather simple function that multiplies the variable X. The given expression is checked only when the function is actually called. If wrong characters are used in the function name, argument name or any other syntactical deviation except for the expression itself, the program aborts with ?SYNTAX ERROR. If you try to use DEF outside programs the BASIC interpreter will report an ?ILLEGAL DIRECT ERROR. If you redefine an already defined function with the same name, the first definition will be overwritten and the new definition is the valid one. It begins with one letter (A-Z) and might optionally followed by letters or digits (0-9), but only the first two characters are significant. The function name follows the same rules as for variable names. Afterwards it can be called with the command FN(). The DEF declaration has to fit into a single line. Except for the variable with the same name of the function argument, all other variables can still be accessed.ĭEF only works within program code. The expression could use the parameter's variable name which acts as a placeholder for the actual value when called by FN. Functions, operands and system variables such as ABS(), AND, ATN(), ASC(), COS(), EXP(), FN(), FRE(), INT(), LEN() LOG(), NOT, PEEK(), POS(), OR, RND(), SGN(), SIN(), SQR(), STATUS (ST), TAN(), TIME (TI) or VAL() are possible. The definition may contain any legitimate mathematical expression consisting of mathematical and logical operands, functions and variables which finally results in a numeric value. The BASIC-command DEF defines a function with exactly one single numeric argument which can be executed with FN afterwards. General Programming-Syntax: DEF FN (parameter name)= Remark: This article describes the BASIC command DEF in BASIC V2 on the Commodore 64. ![]()
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