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<HTML><HEAD><TITLE> Macro/Shell Extensions </TITLE></HEAD><BODY><A NAME="Macro_Language"></A><H2> Macro Language </H2><P>Macros can be called from Macro menu commands, window background menucommands, within the smart-indent framework, from the autoload macro file andfrom the command line.Macro menu and window background menu commands are defined under Preferences-> Default Settings -> Customize Menus. Help on creating items in thesemenus can be found in the section, Help -> Customizing -> Preferences.</P><P>The autoload macro file is a file of macro commands and definitions whichNEdit will automatically execute when it is first started. Its location isdependent on your environment:</P><P><UL> <li>The default place for the file is '$HOME/.nedit/autoload.nm',</li> <li>if the variable $NEDIT_HOME is set in your environment it is located at '$NEDIT_HOME/autoload.nm',</li> <li>if you are using old-style run control files (i.e. $HOME/.nedit is a regular file) it is located in '$HOME/.neditmacro'.</li></UL></P><P>(For VMS, the file is in '$NEDIT_HOME/autoload.nm' if $NEDIT_HOME is set, in'SYS$LOGIN:.neditmacro' otherwise.)</P><P>NEdit's macro language is a simple interpreter with integer arithmetic,dynamic strings, and C-style looping constructs (very similar to theprocedural portion of the Unix awk program). From the macro language, youcan call the same action routines which are bound to keyboard keys and menuitems, as well additional subroutines for accessing and manipulating editordata, which are specific to the macro language (these are listed in thesections titled "<A HREF="macro_subrs.html#Macro_Subroutines">Macro Subroutines</A>", and "<A HREF="actions.html#Action_Routines">Action Routines</A>").</P><P><H3>Syntax</H3></P><P>An NEdit macro language program consists of a list of statements, eachterminated by a newline. Groups of statements which are executed togetherconditionally, such as the body of a loop, are surrounded by curly braces"{}".</P><P>Blank lines and comments are also allowed. Comments begin with a "#" and endwith a newline, and can appear either on a line by themselves, or at the endof a statement.</P><P>Statements which are too long to fit on a single line may be split acrossseveral lines, by placing a backslash "\" character at the end of each lineto be continued.</P><P><H3>Data Types</H3></P><P>The NEdit macro language recognizes only three data types, dynamic characterstrings, integer values and associative arrays. In general strings andintegers can be used interchangeably. If a string represents an integervalue, it can be used as an integer. Integers can be compared andconcatenated with strings. Arrays may contain integers, strings, or arrays.Arrays are stored key/value pairs. Keys are always stored as strings.</P><P><H4>Integer Constants</H4></P><P>Integers are non-fractional numbers in the range of -2147483647 to2147483647. Integer constants must be in decimal. For example:</P><P><PRE> a = -1 b = 1000</PRE></P><P><H4>Character String Constants</H4></P><P>Character string constants are enclosed in double quotes. For example:</P><P><PRE> a = "a string" dialog("Hi there!", "Dismiss")</PRE></P><P>Strings may also include C-language style escape sequences:</P><P><PRE> \\ Backslash \t Tab \f Form feed \" Double quote \b Backspace \a Alert \n Newline \r Carriage return \v Vertical tab</PRE></P><P>For example, to send output to the terminal from which NEdit was started, anewline character is necessary because, like printf, t_print requiresexplicit newlines, and also buffers its output on a per-line basis:</P><P><PRE> t_print("a = " a "\n")</PRE></P><P><H3>Variables</H3></P><P>Variable names must begin either with a letter (local variables), or a $(global variables). Beyond the first character, variables may also containnumbers and underscores `_'. Variables are called in to existence just bysetting them (no explicit declarations are necessary).</P><P>Local variables are limited in scope to the subroutine (or menu itemdefinition) in which they appear. Global variables are accessible from allroutines, and their values persist beyond the call which created them, untilreset.</P><P><H4>Built-in Variables</H4></P><P>NEdit has a number of permanently defined variables, which are used to accessglobal editor information and information about the the window in which themacro is executing. These are listed along with the built in functions inthe section titled "<A HREF="macro_subrs.html#Macro_Subroutines">Macro Subroutines</A>".</P><P><H3>Functions and Subroutines</H3></P><P>The syntax of a function or subroutine call is:</P><P><PRE> function_name(arg1, arg2, ...)</PRE></P><P>where arg1, arg2, etc. represent up to 9 argument values which are passed tothe routine being called. A function or subroutine call can be on a line byitself, as above, or if it returns a value, can be invoked within a characteror numeric expression:</P><P><PRE> a = fn1(b, c) + fn2(d) dialog("fn3 says: " fn3())</PRE></P><P>Arguments are passed by value. This means that you can not return values viathe argument list, only through the function value or indirectly throughagreed-upon global variables.</P><P><H4>Built-in Functions</H4></P><P>NEdit has a wide range of built in functions which can be called from themacro language. These routines are divided into two classes, macro-languagefunctions, and editor action routines. Editor action routines are moreflexible, in that they may be called either from the macro language, or bounddirectly to keys via translation tables. They are also limited, however, inthat they can not return values. Macro language routines can return values,but can not be bound to keys in translation tables.</P><P>Nearly all of the built-in subroutines operate on an implied window, which isinitially the window from which the macro was started. To manipulate thecontents of other windows, use the focus_window subroutine to change thefocus to the ones you wish to modify. focus_window can also be used toiterate over all of the currently open windows, using the special keywordnames, "last" and "next".</P><P>For backwards compatibility, hyphenated action routine names are allowed, andmost of the existing action routines names which contain underscores have anequivalent version containing hyphens ('-') instead of underscores. Use ofthese names is discouraged. The macro parser resolves the ambiguity between'-' as the subtraction/negation operator, and - as part of an action routinename by assuming subtraction unless the symbol specifically matches an actionroutine name.</P><P><H4>User Defined Functions</H4></P><P>Users can define their own macro subroutines, using the define keyword:</P><P><PRE> define subroutine_name { < body of subroutine > }</PRE></P><P>Macro definitions can not appear within other definitions, or within macromenu item definitions (usually they are found in the autoload macro file).</P><P>The arguments with which a user-defined subroutine or function was invoked,are presented as $1, $2, ... , $9. The number of arguments can be read from$n_args.</P><P>To return a value from a subroutine, and/or to exit from the subroutinebefore the end of the subroutine body, use the return statement:</P><P><PRE> return <value to return></PRE></P><P><H3>Operators and Expressions</H3></P><P>Operators have the same meaning and precedence that they do in C, except for^, which raises a number to a power (y^x means y to the x power), rather thanbitwise exclusive OR. The table below lists operators in decreasing order ofprecedence.</P><P><PRE> Operators Associativity () ^ right to left - ! ++ -- (unary) * / % left to right + - left to right > >= < <= == != left to right & left to right | left to right && left to right || left to right (concatenation) left to right = += -= *= /= %=, &= |= right to left</PRE></P><P>The order in which operands are evaluated in an expression is undefined,except for && and ||, which like C, evaluate operands left to right, but stopwhen further evaluation would no longer change the result.</P><P><H4>Numerical Operators</H4></P><P>The numeric operators supported by the NEdit macro language are listed below:</P><P><PRE> + addition - subtraction or negation * multiplication / division % modulo ^ power & bitwise and | bitwise or</PRE></P><P>Increment (++) and decrement (--) operators can also be appended or prependedto variables within an expression. Prepended increment/decrement operatorsact before the variable is evaluated. Appended increment/decrement operatorsact after the variable is evaluated.</P><P><H4>Logical and Comparison Operators</H4></P><P>Logical operations produce a result of 0 (for false) or 1 (for true). In alogical operation, any non-zero value is recognized to mean true. Thelogical and comparison operators allowed in the NEdit macro language arelisted below:</P><P><PRE> && logical and || logical or ! not > greater < less >= greater or equal <= less or equal == equal (integers and/or strings) != not equal (integers and/or strings)</PRE></P><P><H4>Character String Operators</H4></P><P>The "operator" for concatenating two strings is the absence of an operator. Adjoining character strings with no operator in between means concatenation:</P><P><PRE> d = a b "string" c t_print("the value of a is: " a)</PRE></P><P>Comparison between character strings is done with the == and != operators,(as with integers). There are a number of useful built-in routines forworking with character strings, which are listed in the section called "<A HREF="macro_subrs.html#Macro_Subroutines">Macro Subroutines</A>".</P><P><H4>Arrays and Array Operators</H4></P><P>Arrays may contain either strings, integers, or other arrays. Arrays are associative, which means that they relate two pieces of information, the keyand the value. The key is always a string; if you use an integer it isconverted to a string.</P><P>To determine if a given key is in an array, use the 'in' keyword.</P><P><PRE> if ("6" in x) <body></PRE></P><P>If the left side of the in keyword is an array, the result is true if everykey in the left array is in the right array. Array values are not compared.</P><P>To iterate through all the keys of an array use the 'for' looping construct.Keys are not guaranteed in any particular order:</P><P><PRE> for (aKey in x) <body></PRE></P><P>Elements can be removed from an array using the delete command:</P><P><PRE> delete x[3] # deletes element with key 3 delete x[] # deletes all elements</PRE></P><P>The number of elements in an array can be determined by referencing thearray with no indices:</P><P><PRE> dialog("array x has " x[] " elements", "OK")</PRE></P><P>Arrays can be combined with some operators. All the following operators only compare the keys of the arrays.</P><P><PRE> result = x + y (Merge arrays)</PRE></P><P>The 'result' is a new array containing keys from both x and y. Ifduplicates are present values from y are used.</P><P><PRE> result = x - y (Remove keys)</PRE></P><P>The 'result' is a new array containing all keys from x that are not in y.</P><P><PRE> result = x & y (Common keys)</PRE></P><P>The 'result' is a new array containing all keys which are in both x and y.The values from y are used.</P><P><PRE> result = x | y (Unique keys)</PRE></P><P>The 'result' is a new array containing keys which exist in either x or y, but not both.</P><P>When duplicate keys are encountered using the + and & operators, the values from the array on the right side of the operators are used for the result.All of the above operators are array only, meaning both the left and rightsides of the operator must be arrays. The results are also arrays.</P><P>Array keys can also contain multiple dimensions:</P><P><PRE> x[1, 1, 1] = "string"</PRE></P><P>These are used in the expected way, e.g.:</P><P><PRE> for (i = 1; i < 3; i++) { for (j = 1; j < 3; j++) { x[i, j] = k++ } }</PRE></P><P>gives the following array:</P><P><PRE> x[1, 1] = 0 x[1, 2] = 1 x[2, 1] = 2 x[2, 2] = 3</PRE></P><P>Internally all indices are part of one string, separated by the string $sub_sep (ASCII 0x18). The first key in the above example is in fact</P><P><PRE> ["1" $sub_sep "1"]</PRE></P><P>If you need to extract one of the keys, you can use split(), using $sub_sep as the separator.</P><P>You can also check for the existence of multi-dimensional array by looking for $sub_sep in the key.</P><P>Last, you need $sub_sep if you want to use the 'in' keyword.</P><P><PRE> if ((1,2) in myArray) {..}</PRE></P><P>doesn't work, but</P><P><PRE> if (("1" $sub_sep "2") in myArray) {..}</PRE></P><P>does work.</P><P><H3>Looping and Conditionals</H3></P><P>NEdit supports looping constructs: for and while, and conditional statements:if and else, with essentially the same syntax as C:</P><P><PRE> for (<init>, ...; <condition>; <increment>, ...) <body></PRE></P><P><PRE> while (<condition>) <body></PRE></P><P><PRE> if (<condition>) <body></PRE></P><P><PRE> if (<condition>) <body> else <body></PRE></P><P><body>, as in C, can be a single statement, or a list of statements enclosedin curly braces ({}). <condition> is an expression which must evaluate totrue for the statements in <body> to be executed. for loops may also containinitialization statements, <init>, executed once at the beginning of theloop, and increment/decrement statements (or any arbitrary statement), whichare executed at the end of the loop, before the condition is evaluated again.</P><P>Examples:</P><P><PRE> for (i=0; i<100; i++) j = i * 2</PRE></P><P><PRE> for (i=0, j=20; i<20; i++, j--) { k = i * j t_print(i, j, k) }</PRE></P><P><PRE> while (k > 0) { k = k - 1 t_print(k) }</PRE></P><P><PRE> for (;;) { if (i-- < 1) break }</PRE></P><P>Loops may contain break and continue statements. A break statement causes anexit from the innermost loop, a continue statement transfers control to theend of the loop.<P><HR></P><P></P></BODY></HTML>⌨️ 快捷键说明
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