--- name: "icmscript" section: "7" platform: "linux" package: "icmake" version: "13.07.00-1" release: "Arch Linux 2026-11-01" platforms: ["linux"] url: "https://new.carta.tech/icmscript" --- # icmscript(7) The C-like icmake scripting language ## NAME icmscript - The **C**-like *icmake* scripting language ## DESCRIPTION **Icmake**(1) is a generic tool handling program maintenance that can be used as an alternative for [**make**(1)](/make/1.md). It’s a generic tool in that *icmake*-scripts, written in a language closely resembling the **C** programming language, can perform tasks that are traditionally the domain of scripting languages. **Icmake** allows programmers to use a programming language (closely resembling the **C**-programming language) to define the actions that are required for (complex) program maintenance. For this, **icmake** offers various special operators as well as a set of support functions that have shown their usefulness in program maintenance. This man-page covers the **icmake** scripting language in de following sections: - o **DATA TYPES**\ \- *int, list, string*, and *void* (for functions); - o **OUTLINE**\ \- outline of **icmake** scripts: what are their requirements, the structure and organization of their *main*-functions. - o **PREPROCESSOR DIRECTIVES**\ \- supported preprocessor directives, like *#include* and *#define*; - o **PREDEFINED CONSTANTS**\ \- like *O\_FILE, OFF*, and *S\_IFREG*; - o **OPERATORS**\ \- like *+, younger*, and casts - o **FLOW CONTROL**\ \- *if, for, while*, etc. (the *switch* is not available); - o **PREDEFINED FUNCTIONS**\ \- executing programs, changing directories, operations on *string* and *list* type variables, etc.. Functions are marked as *INT FUNCTIONS*, *LIST FUNCTIONS*, *STRING* *FUNCTIONS* - o **USER DEFINED FUNCTIONS**\ \- at least *main*, with or without its common parameters *argc, argv,* and *envp*. ## DATA TYPES **Icmake** supports the following five data and value types: - o *ASCII character constants*\ ASCII character constants are ascii-characters, surrounded by single or double quotes. Single characters (e.g., *’a’*) represent the character itself. Standard escape sequences (e.g., *’\\n’*) are supported and are converted to their well-known values (e.g., *’\\n’* represents ascii value 10 (decimal)). Non-standard escape sequences (e.g., *’\\x’*) are converted to the ascii character following the escape character (so *’\\x’* equals *’x’*). Escaped sequences consisting of three octal digits represent the ascii character corresponding to the octal value, modulo 256 (e.g., *’\\113’* represents *’K’*). Escape sequences consisting of an x followed by two hexadecimal digits represent the ascii character corresponding to the hexadecimal value (e.g., *’\\x4b’*, also representing *’K’*); - - o *int*\ Integral values, ranging from *-0x8000* through *0x7fff*. *int* constants may be specified as decimal numbers (starting with digits 1 through 9), octal numbers (starting with 0, followed by one or more octal digits), hexadecimal numbers (starting with 0x, followed by one or more hexadecimal digits), or as *ASCII* character constants; - - o *string*\ Text values: text (or \`string’) constants are delimited by double or single quotes. Multiple string constants may be concatenated, but a single string constant may not span multiple lines. Multiple string constants, only separated by white space (i.e., blanks, newlines, comment) are concatenated and are considered one single string constant. To indicate an end-of-line in a string constant use the *\\n* escape sequence; - If arithmetic expressions use at least one *int* operand then those expressions may also contain single character ASCII constants using double or single quotes. In those cases they represent the ascii-values of their characters. - Conversely, ASCII character constants using single quotes may be used in situations where string operands are expected; - - o *list*\ A *list* is a data structure containing a series of individually accessible *string* values. When a list contains elements, its first element has index 0; - Lists may be written to the standard output stream or to file (using *printf* or *fprintf*). Lists can also be inserted into *string* variables using the function *strformat*. In these cases all (space delimited) elements of the lists are inserted into their destinations; - Lists can also be defined as constants. They consist of an optional series of comma separated string constants surrounded by a pair of square brackets. E.g., ``` list words = ["a", "list", "constant"]; ``` - - o *void*\ The type *void* is used when defining functions which do not return values. Alternatively, functions may return *int, string* or *list* values (cf. section **USER DEFINED FUNCTIONS**). Variables can be defined at the global level and inside functions (not only at the top of compound statements but also between statements and in the initialization section of for- and if-statements). When defined inside functions, the standard **C** scoping and visibility rules apply. Variables are strongly typed, and cannot have type *void*. Variables may be initialized when they are defined. Initializations are expressions which may use predefined or user-defined functions, constant values, and values of variables. Functions or variables that are used for initialization must be visible at the initialization point. ## OUTLINE **Icmake** scripts require a user-defined function *main*. The function *main* has three optional parameters, which may be omitted from the last one (*envp*) to the first one (*argc*), like in **C**. Its full prototype is: ``` void main(int argc, list argv, list envp) ``` or ``` int main(int argc, list argv, list envp) ``` When a *void main* function ends (using a *return;* statement or when its execution reaches its body’s closing curly) the value 0 is returned to the operating system. When *int main* functions end using *return* statements then those statements must be provided with *int*-expressions. It’s OK when the execution of an *int main* function reaches its body’s closing curly, in which case 0 is automatically returned to the operating system In *main* the parameter - o *argc* represents the number of elements in *argv*; - - o *argv* contains the arguments, with element 0 being equal to the name of the *.bim* file, that were passed to the *.bim* file. The **OPTIONS** section of the [**icmake**(1)](/icmake/1.md) manpage covers how these arguments are forwarded to the **icmake** script using options *-e, -s,* and *-t*. - - o *envp* contains the \`environment’ variables. The function *listlen* can be used to determine the number of its elements. Elements in *envp* use the format *variable=value*. Alternatively, the (predefined) function *getenv* can be used to retrieve a specific environment variable immediately. Example (the implementations of the user-defined functions *usage,* *modified,* and *compile* are left as an exercise for the reader): ``` void main(int argc, list argv) { if (argc == 1) usage(argv[0]); if (list toCompile = modified("*.cc")) { for (int idx = listlen(toCompile); idx--; ) compile(toCompile[idx]); } } ``` When executing an **icmake** script **icmake’s** run-time support system first initializes all all global variables in the order of their definitions. Following this the function *main* is called. The script ends when *main* returns or when the function *exit* is called by the script. ## PREPROCESSOR DIRECTIVES Before actually compiling **icmake** scripts they are first pre-processed by the **icmake** pre-processor. The pre-processor removes comment, includes files specified by *include*-directives, and processes *#define* and comparable directives. The following preprocessor directives are recognized: - o comment:\ standard **C** comment (everything from */\** through *\*/*) as well as comment-to-end-of-line (starting at *//*, continuing to the end of the line) is ignored; - - o Shell startup: The first line of the **icmake**-script may start with *#!path*, where *path* defines the (usually absolute) location of the **icmake** program. By making the script executable, it can be called without explicitly calling **icmake**. - E.g., if the first line of an (executable) icmake script ’icm’ (without extension) contains ``` #!/usr/bin/icmake -t. ``` then *icm* can be issued as a command, interpreting the remaining lines of the script as an **icmake** source which is compiled and then executed by **icmake**. The [**icmake**(1)](/icmake/1.md) man-page’s section **EXECUTING** **ICMAKE SCRIPTS** covers the elements of the first line of **icmake** scripts. - - o *#include "filename"*\ The file *filename* is included at the location of the directive; - - o *#include \*\ The file *filename* is included at the location of the *#include* directive; *filename* is searched in the colon-separated directories specified by the *IM* environment variable. The first occurrence of *filename* in the directories specified by the *IM* environment variable is used; - - o *#define identifier \[definition\]*\ The text *identifier* is replaced by *definition*. The definition may contain references to already defined identifiers, using the syntax *${identifier}*. If the *${identifier}* hasn’t been defined (yet), the literal text *${identifier}* is used. To prevent infinite recursion at most 100 *${identifier}* replacements are accepted; - If the last character on a line is a backslash (*\\*) then definitions continue at the next line. (the backslash is not included in the definition). The preprocessor concatenates double-quoted strings. Double quoted strings themselves may not span multiple lines. Multiple blanks (outside of double quoted strings) in definitions are contracted to a single space character; - Following the *#define’s* identifier a definition may optional be provided. If omitted, the macro is defined, so it can be used in *#[if(n)](/if/n.md)def* directives (see below), but in those cases these intentifiers are simply removed from **icmake** code statements. - - o *#ifdef identifier*\ If the *identifier* macro was defined the next block of code (until a matching *#else* or *#endif* directive was read) is byte-compiled. Otherwise, the code block is ignored; - - o *#ifndef identifier*\ If the *identifier* macro was *not* defined the next block of code (until a matching *#else* or *#endif* directive was detected) is byte-compiled. Otherwise, the code block is ignored; - - o *#else*\ Terminates *#ifdef* and *#ifndef* code blocks, reversing the acceptance decision about the following code block. Only one *#else* directive can be associated with *#[if(n)](/if/n.md)def* directives; - - o *#endif*\ Terminates the code block starting beyond the matching *#ifdef*, *#ifndef* or *#else* directive. Associated *#[if(n)](/if/n.md)def, #else*, and *#endif* directives must be specified in the same file; - - o *#undef identifier* \ Remove *identifier* from the set of defined symbols. This does not affect the specification of any previously defined symbols using *identifier’s* definition. If *identifier* hasn’t been defined a warning is issued. ## PREDEFINED CONSTANTS The following predefined *int* constants are available (the functions listed in the *intended for* column are described in the upcoming sections covering the predefined functions): | | | | | --- | --- | --- | | | O\_ALL | 8 | makelist | | | O\_FILE | 1 | makelist | | O\_SUBDIR | 4 | makelist | | OFF | 0 | echo | | ON | 1 | echo | | | P\_NOCHECK | 1 | system calls | | S\_IEXEC | 32 | stat | | | S\_IFDIR | 2 | stat | | S\_IFREG | 4 | stat | | | S\_IWRITE | 16 | stat | | | The following constants are architecture dependent: | | | | --- | --- | | | unix | Unix, usually with GNU’s gcc compiler | | | linux | x86 running Linux (usually with gcc) | | LINUX | may alternatively be available | | M\_SYSV, M\_UNIX | x86 running SCO/Unix | | \_POSIX | \_SOURCE Unix with Posix compliant compiler | | \_\_hpux | HP-UX, with the native HP compiler | | | ## OPERATORS Since **icmake** version 10.00.00 the *\<\<* operator can be used like the **C++** insertion operator. See the description of the functions *printf* and *fprintf* below. **int-operators:** All **C** operators (including the ternary operator) are available (except for pointer operators, as **icmake** does not support pointers). They operate like their **C**-programming language’s counterparts. Comparison operators return 1 if the comparison is true, otherwise 0 is returned. **string-operators:** For *string* variables and/or constants the following operators are available (*lhs* and *rhs* are *string* variables or constants): - o *lhs + rhs*: returns a new *string* value containing the concatenation of *strings lhs* and *rhs*. Note that *string* constants can also directly be concatetated (not using the *+* operator), e.g., the following two lines both define the string *"hello world"*: ``` "hello " "world" "hello " + "world" ``` - - o *lhs += rhs*: *lhs* must be a *string* variable, to which the *string* variable or value *rhs* is appended; - - o string comparisons: operators *== != \<= \>= \< \> !=* and *==* return 1 if the comparison is true, otherwise 0. The ordering operators (like *\<* and *\>=*) use the (case sensitive) character ordering defined by the *ASCII* character set; - - o *!lhs*: the boolean *!* (not) operator returns 1 if the *string* *lhs* is empty, otherwise 0 is returned. Strings merely containing white-space characters are not empty; - - o *lhs younger rhs, lhs newer rhs*: returns 1 if file *lhs* is more recent than file *rhs*. E.g., *"source.cc" newer "source.o"*. The files *lhs* and *rhs* do not have to exist: - o if both don’t exist 0 is returned, - o if *lhs* doesn’t exist 0 is returned, - o if *rhs* doesn’t exist, 1 is returned, - o if they are equally old 0 is returned. - The function *exists()* (see below, section **PREDEFINED** **FUNCTIONS**) can be used to test whether a file exists; - - o *lhs older rhs*: returns 1 if file *lhs* is older than file *rhs*. E.g., *"libprog.a" older "source.o"*. The files *lhs* and *rhs* do not have to exist: - o if both don’t exist 0 is returned, - o if *lhs* doesn’t exist 1 is returned, - o if *rhs* doesn’t exist, 0 is returned, - o if they are equally old 0 is returned. - - o *\[\]*: the index operator returns a character from a string variable or constant. A string is returned as an *rvalue*. Thus, the following statement compiles OK: ``` lhs = rhs[3]; ``` but the following statement won’t compile (as *lhs\[3\]* is an *rvalue*): ``` lhs[3] = "a"; ``` If an invalid (out of bounds) index value is specified an empty string is returned. - - o The *backtick* operator (*\`string cmd\`*)\ A string placed between two backticks is executed as a separate command. Different from the *exec* and *system* calls the backtick operator collects the standard output produced by \`cmd’ returning this output as a list. - The elements of the list contain the subsequent lines of output (including a final newline, if present) produced by \`cmd’. A command that could be executed but that did not produce any output returns a list containing one string element, which is empty. - An empty list indicates that the command could not be executed. - The command’s standard error stream output is ignored by the backtick operator. However, standard shell redirection may be used to collect the standard error stream’s output. - Example: ``` printf << `"ls"`; // prints the elements in // the current directory ``` Note that the backtick operator requires a string argument: either a string constant or a string variable. - The function *eval(string cmd)* behaves exactly like the backtick operator: they are synonyms. **list-operators:** For *list* variables and/or values the following operators are available: - o *lhs + rhs*: returns a new *list* value containing the concatenation of the values of *lists lhs* and *rhs*. This is *not* a set operation: if an element appears both in *lhs* and in *rhs*, then both will appear in the resulting list (set-addition is provided by the function *listunion*); - - o *lhs - rhs*: returns a new *list* value containing the elements in *lhs* that are not present in *rhs*. This is a set-difference operation. The ordering of the remaining elements in the returned list is equal to the ordering of those elements in *lhs*; - - o *lhs += rhs*: elements in *rhs* are added to the elements in *lhs*, which must be a *list* variable. This is *not* a set operation; - - o *lhs -= rhs*: elements in *rhs* are removed from the elements in *lhs*. This is a set operation: all elements of *lhs* that are found in *rhs* are removed from *lhs*. The ordering of the remaining elements in *lhs* is not altered; - - o list equality comparisons: operators *!=* and *==* may be applied to *list* values or variables. Operator *==* returns 1 if both lists have element-by-element identical elements, otherwise 0 is returned. Operator *!=* reverses the result of *==*; - - o *!lhs*: the boolean *!* operator returns 1 if the *list lhs* is empty, otherwise 0 is returned; - - o *\[\]*: the index operator retrieves an element from a list variable: it returns a string as an *rvalue*. Thus, the following statement compiles OK: ``` // assume lst is a list, str is a string str = lst[3]; ``` but the following statement won’t compile (as *lst\[3\]* is an *rvalue*): ``` lst[3] = str; ``` If an invalid (out of bounds) index value is specified an empty string is returned. **casting:** Type-casts using the standard **C**-style cast-operator can be used to cast: - o strings to ints and vice versa (*(int)"123", (string)55*)\ If the content of a string does not represent a (decimal) *int* value 0 the cast returns 0; - - o Strings to lists (*list lst = (list)"hello"*): this returns a list having one element (*hello*) (note that casting a string to a list as shown is overkill as *list lst = \["hello"\]* performs the same initialization). ## FLOW CONTROL **Icmake** offers a subset of **C**’s flow control statements. They can be used as in the **C** programming language. - o *expression ;*\ The plain expression statement. - Insert-expression statements are defined for the functions *fprintf* and *printf*. Expression statements may start with *printf \<\<* or *fprintf \<\< filename \<\<*. The values of all subsequent expressions, separated by *\<\<* operators (which in this context are called *insertion operators*) are written to the standard output stream (when using *printf \<\<*), or to the file whose name is provided in the *string filename* (when using *fprintf \<\< filename \<\<*). Examples: ``` printf << "hello" << ’ ’ << "world" << ’\n’; fprintf << "out.txt" << "hello" << ’ ’ << "world" << ’\n’; ``` - - o The compound statement \ Variables may be defined and initialized inside compound statements at locations where expression statements can also be used. The *visibility* of variables starts at their points of definition; - - o *if (\[definition;\] condition) statement*\ The *\[definition;\]* phrase is optional. If used it defines a type followed by a comma-separated list of variables which may be provided with initialization expressions. - The condition phrase is required, and may define and initialize a variable. E.g, ``` if (string str = getText()) process(str); ``` In this example, *process* is not called if *getText()* returns an empty string. - Variables defined in the definition and condition phrases do not exist either before or after the *if* statement.\ - - o *if (\[definition;\] condition) statement1 else statement2*\ Acts like the previous statement. If the condition is true *statement1* is executed; if the condition is false *statement2* is executed; - - o *for (init; condition; increment) statement*\ Variables (of a single type) may be initialized (and optionally defined) in the *init* section. The condition phrase may define and initialize a variable. The *init*, *condition* and *increment* sections may remain empty. An empty condition section is interpreted as \`always *true*’; - - o *while (condition) statement*\ Inside the condition a variable may be defined and initialized. - A complementary *do ... while()* statement is not available. Note that when a variable is defined and initialized in the condition section the initialization expression is executed at each iteration of the *while* statement. Thus the following statement never ends, and displays a never ending stream of values 10: ``` while (int x = 10) printf(x--, "\n"); ``` - - o *return;*, and *return expression;*\ Plain *return* statements can be used in *void* functions, and *return expression* statements are used in other type of functions. - - o *break*\ *break;* statements can only be used in *for* and *while* statements, ending those statements; - - o *continue*\ *continue;* statements can only be used in *for* and *while* statements, continuing their next iteration. ## PREDEFINED FUNCTIONS **Icmake** provides the following predefined functions, which can be used anywhere in **icmake** scripts. In the following overview the functions are ordered by categories, and within categories they are ordered alphabetically by function name. Five categories are distinguished: - o Functions operating on ints (see *INT FUNCTIONS* below):\ these functions receive *int* arguments, processing those arguments; - - o Functions operating on strings (see *STRING FUNCTIONS* below):\ these functions operate on the strings which are passed to these functions as arguments; - - o Functions operating on lists (see *LIST FUNCTIONS* below):\ these functions operate on the lists which are passed to these functions as arguments; - - o Functions manipulating file system entries (see *FILESYSTEM* *FUNCTIONS* below):\ these functions receive the names of file-system entries (files, directories, etc.) as their *string* arguments. - Note that these functions are not listed in the *STRING FUNCTIONS* section, as they do not directly operate on their *string* arguments, but merely use those arguments to identify file system entries. - On the other hand, functions like *change\_base* do not operate on file-system entries and are therefore entries in the *STRING* *FUNCTIONS* section; - - o System-related functions (see *SYSTEM FUNCTIONS* below):\ these functions interface to facilities provided by the operating system, like executing programs or changing the script’s environment variables. Some of these functions use specialized support functions, which are also included in this section. **INT FUNCTIONS:** - o *string ascii(int value)*\ returns *value* as a string: *ascii(65)* returns the string *"A"*; - - o *echo(int opt)*\ controls echoing of called programs (and their arguments), specify *OFF* if echoing is not requested. By default *echo(ON)* is active. **STRING FUNCTIONS:** - o *int ascii(string str)*\ returns the first character of *str* as an in: *ascii("A")* returns 65; - - o *string change\_base(string file, string base)*\ returns *file* whose base name is changed into *base*: *change\_base("/path/demo.im", "out")* returns *"/path/out.im"*; - - o *string change\_ext(string file, string ext)*\ returns *file* whose extension is changed into *ext*: *change\_ext("source.cc", "o")* returns *"source.o"*. The extension of the returned *string* is separated from the file’s base name by a single dot (e.g., *change\_ext("source.", ".cc")* returns *"source.cc"*); - - o *string change\_path(string file, string path)*\ return *file* whose path is changed into *path*: *change\_path("tmp/binary", "/usr/bin")* returns *"/usr/bin/binary"*. To remove the path specify *path* as an empty string; - - o *string element(int index, string var)*\ acts identically to the index operator: refer to the index (*\[\]*) operator in section **OPERATORS**; - - o *string get\_base(string file)*\ returns the base name of *file*. The base name is the file without its path prefix and without its extension. The extension is all information starting at the final dot in the filename. If no final dot is found, the file name is the base name. E.g., the base name of *a.b* equals *a*, the base name of *a.b.c* equals *a.b*, the base name of *a/b/c* equals *c*; - - o *string get\_dext(string file)*\ returns the extension of *file*, including the separating dot (hence the *d* in *dext*). The extension is all information starting at the filename’s final dot. If *file* does not have a final dot then an empty string is returned; - - o *string get\_ext(string file)*\ returns the extension of *file*, without the separating dot. The extension are all characters in *file* starting at *file’s* final dot. If no final dot is found, an empty string is returned; - - o *string get\_path(string file)*\ returns *file’s* path-prefix. The path prefix is all information up to (and including) the final directory separator (which is, depending on the operating system, a forward slash or a backslash). If *file* does not contain a path-element, then an empty string is returned; - - o *string resize(string str, int newlength)* returns a copy of string *str*, resized to *newlength* characters. If *newlength* is negative then an empty string is returned, if *newlength* exceeds *str’s* length then the newly added characters are initialized to blank spaces; - - o *int strchr(string str, string chars)*\ returns the first index in *str* where any of the characters in *chars* is found, or -1 if *str* does not contain any of the characters in *chars*; - - o *int strfind(string haystack, string needle)*\ returns index in *haystack* where *needle* is found, or -1 if *needle* is not found in *haystack*; - - o *string strformat(string format, argument(s))*\ returns a string constructed from the *format* string containing placeholders %1 .. %2 to refer to arguments following the format string. The specification %1 refers to the first argument following the format string. If fewer arguments than *n* are provided then additional 0 arguments are provided by **icmake**. Example:\ ``` void main() { string s2 = = strformat("%1 %2 %1\n", 10, 20); printf("s2 = ", s2); // shows: s2 = 10 20 10 } ``` - - o *int strlen(string str)*\ returns the number of characters in *str* (not counting the terminating NUL-character); - - o *string strlwr(string str)*\ returns a lower-case duplicate of *str*; - - o *list strtok(string str, string separators)*\ returns a list containing all substrings of *str* separated by one or more (consecutive) characters in *separators*: *strtok("hello icmake’s+world", " +")* returns a list containing the three strings *"hello"*, *"icmake’s"*, and *"world"*; - - o *string strupr(string str)*\ returns an upper-case duplicate of *str*. - - o *string substr(string text, int offset, int count)*\ returns a substring of *text*, starting at *offset*, consisting of *count* characters. If *offset* exceeds (or equals) the string’s length or if *count \<= 0*, then an empty string is returned. If *offset* is less than 0 then *offset = 0* is used. If *offset +* *count* exceeds *text’s* length then the available substring starting at *text\[offset\]* is returned (which may be empty); - - o *string trim(string str)*\ returns a copy of *str* without leading and trailing white spaces; - - o *string trimleft(string str)*\ returns a copy of *str* without leading white spaces; - - o *string trimright(string str)*\ Returns a copy of *str* without trailing white spaces. **LIST FUNCTIONS:** - o *string element(int index, list var)*\ acts identically to the index operator: refer to the index (*\[\]*) operator in section **OPERATORS**; - - o *int listfind(list lst, string str)*\ returns the smallest index in *lst* where the string *str* is found, or -1 if *lst* does not contain *str*; - - o *int listlen(list l)*\ returns the number of elements in *list*; - - o *list listunion(list lhs, list rhs)*\ returns a list containing the union of the elements in *lhs* and the elements of *rhs*. The original order of the elements in *lhs* is kept. Subsequent elements in *rhs* that are not available in *lhs* are added to the end of *lhs*; - - o *list listunion(list lst, string str)*\ returns a list containing the union of the elements in *lst* and *str*. The original order of the elements in *lhs* is kept. If *rhs* is not available in *lhs* then it is added to the end of *lhs*. **FILESYSTEM FUNCTIONS:** - o *string chdir(\[int check,\] string dir)*\ changes the script’s working directory to *dir* (which may be specified as absolute or relative to the script’s current working directory). The first argument is optional: if omitted and changing the working directory fails then the **icmake**-script ends with exit value 1; by specifying *P\_NOCHECK* the function won’t terminate the script but merely returns the script’s current working directory. The script’s working directory after completing the change-dir request is returned as an absolute path, ending in a \`/’ directory separator. - Use *chdir(".")* to merely obtain the current working directory; use *chdir("")* to change-dir to the script’s startup working directory; - - o *int exists(string file)*\ if *file* exists, 1 is returned, otherwise 0 is returned; - - o *list fgets(string file, list offset)*\ the next line found at offset value *offset\[3\]* is read from *file*. Pass an empty list to *fgets* to read *file* from its beginning. - The returned list has four elements: - o its first element (\[0\]) contains the read line (without the line’s *\\n* line terminator); - - o its second element (\[1\]) contains the line’s *\\n* line terminator (or an empty string if the line was not terminated by a *\\n*); - - o its third element (\[2\]) contains the string *OK* if the line was successfully read and *FAIL* if reading from file failed; - - o its fourth element (\[3\]) contains the offset beyond the last read byte. - To read multiple lines, pass the returned list as argument to *fgets*: ``` list ret; while (ret = fgets("filename", ret)) process(ret); ``` Be careful not to define *list ret* in *while’s* condition, as this will reset *ret* to an empty list at each iteration; - - o *int fprintf(string filename, argument(s))*\ appends all (comma or left-shift (insertion) operator separated) arguments to the file *filename*. Returns the number of printed arguments. - If the first argument (following *filename*) contains placeholders (*%1, %2, ... %n*) then that argument is considered a format string (see also the function *strformat* in the string functions section for additional information about format strings). Some examples: ``` fprintf("out", "hello", "world", ’\n’); fprintf << "out" << "hello" << "world" << ’\n’; fprintf("out", "%1 %2\n", "hello", "world"); // 1 fprintf << "out" << "hello" << ’ ’ << "world" << ’\n’; // 2 fprintf << "out" << "%1 %2\n" << "hello" << "world"; // 3 ``` When writing statement 1 using insertion operators (cf. the expression statement description in section *FLOW CONTROL*) statement 2 would normally be encountered, although statement 3, using the format string, would still be accepted; - - o *string getch()*\ returns the next pressed key as a string (pressing the \`Enter’-key is not required). The pressed key is not echoed. If the key should be echoed use, e.g., *printf(getch())*; - - o *string gets()*\ returns the next line read from the keyboard as a *string*. The line contains all entered characters until the \`Enter’-key was pressed. The \`Enter’-key’s value itself is not stored in the returned string; - - o *list makelist(\[int type = O\_FILE\], string mask)*\ the argument *type* is optional, in which case *O\_FILE* is used. *Makelist* returns a list of all *type* file-system entries matching *mask*. E.g., *makelist("\*.c")* returns a list containing all files ending in *.c*. For *type* one of the following set of values can be used to obtain a more specific selection of directory entries: | | | | | --- | --- | --- | | symbol | meaning | | | O\_ALL | obtain all directory entries | | | O\_DIR | obtain all directories, including . and .. | | | O\_FILE | obtain a list of regular files | | | O\_SUBDIR | obtain all directories except for . and .. | | | | In Unix-type operating systems the pattern *\** does not match entries starting with a dot (hidden entries). To obtain a list of such entries use the pattern *.\**; - - o *list makelist(\[int type = O\_FILE,\] string mask, {newer,older,younger},* *string comparefile)*\ the (optional) parameter *type* may be specified as in the previous variant of *makelist*. The third parameter must be either *newer* (or *younger*) or *older*. A list of all file-system entries matching mask which are, resp., newer or older than a provided *comparefile* is returned. Note that *newer* and *younger* are operators, not strings; - - o *int printf(argument(s))*\ the function’s (comma or left-shift (insertion) operator separated) arguments are written to the standard output file (cf. the expression statement description in section *FLOW CONTROL* and this section’s description of the *fprintf* function). If the first argument contains *%1, %2, ... %n* specifications then it’s considered a format string (see also the function *strformat* in the *STRING FUNCTIONS* section for additional information about format strings). Like *fprintf printf* returns the number of printed arguments; - - o *list stat(\[int check,\] string entry)*\ Returns [**stat**(2)](/stat/2.md) information of directory entry *entry* as a list. The first argument is optional: if omitted and calling the system *stat* function fails then the **icmake**-script ends with exit value 1; by specifying *P\_NOCHECK* the function won’t terminate the script but returns the return value (-1) of the system *stat* function. - The returned list has two elements: - its first element (\[0\]) holds the entry’s attributes. Attributes are returned as the file type and mode of the specified file (cf. [**stat**(2)](/stat/2.md) and [**inode**(7)](/inode/7.md)). E.g., ``` S_IRUSR - owner has read permission S_IWUSR - owner has write permission S_IXUSR - owner has execute permission S_IFSOCK - socket S_IFLNK - symbolic link S_IFREG - regular file S_IFBLK - block device S_IFDIR - directory S_IFCHR - character device S_IFIFO - FIFO ``` its second element (\[1\]) contains the entry’s size in bytes. If *P\_NOCHECK* was specified and ’entry’ doesn’t exists then a list having one element is returned containing -1. **SYSTEM FUNCTIONS:** - o *void arghead(string str)*\ support function of *exec()* (see also below at *exec()*): defines the \`argument head’ that is used with *exec()*. By default, the \`argument head’ is an empty string. The argument head is text that is prefixed to all *exec* arguments, like a directory in which provided arguments are found; - - o *void argtail (string str)*\ support function of *exec()* (see also below at *exec()*): defines the \`argument tail’ that is used with *exec()*. By default, the \`argument tail’ is an empty string. The argument tail is text that is appended to all *exec* arguments, like the extensions of files that are passed as arguments to *exec*; - - o *cmdhead(string str)*\ support function of *exec()* (see also below at *exec()*). Defines a \`command head’ that is used with *exec()*. By default it is an empty string. It can be used to specify, e.g., compiler options when the arguments themselves are modified by *arghead* and *argtail*. The *cmdhead* argument itself is not modified by *arghead* or *argtail*; - - o *cmdtail(string str)*\ support function of *exec()* (see also below at *exec()*). Defines a \`command tail that is used with *exec()*. By default it is an empty string. It can be used to specify a final argument (not modified by *arghead* and *argtail*); - - o *list eval(string str)*\ this function can be used instead of the backtick operator (cf. section *OPERATORS*). The example provided with the backtick operator could therefore also have been written like this: ``` printf << eval("ls"); // prints the elements in the current // directory ``` As mentioned at the backtick operator: the elements of the list contain the subsequent lines of output (including a final newline, if present) produced by \`cmd’. A command that could be executed but that did not produce any output returns a list containing one string element, which is empty. - An empty list indicates that the command could not be executed. - - o *int exec(\[int check,\] string cmd, argument(s))*\ Executes the command *cmd* with (optional) arguments. Each argument is prefixed by *arghead* and postfixed by *argtail*. Note that no blanks are inserted between *arghead*, argument(s), and *argtail*. The thus modified arguments are concatenated, separated by single blanks. *Cmdhead* is inserted between *cmd* and the first argument (delimited by single blanks) and *cmdtail* is appended to the arguments, separated by a single blank. *PATH* is searched to locate *cmd*. 0 is returned. - The first argument is optional: if omitted and the command does not return 0 the **icmake** script terminates. By specifying *P\_NOCHECK* *exec* won’t terminate the script but returns the called command’s exit status, or *0x7f00* if the command wasn’t found. - The remaining arguments may be ints, strings or lists. Int and list arguments are cast to strings. Their string representations are then appended to *cmd*; - - o *int execute(\[int checking,\] string cmd, string cmdhead,* *string arghead, argument(s), string argtail, string cmdtail)*\ Same functionality as the previous function, but the *cmdhead,* *arghead, argtail,* and *cmdtail* are explicitly specified (and are reset to empty strings after executing *cmd*); - - o *exit(expression)*\ Ends the execution of an **icmake**-script. The *expression* must evaluate to an *int* value, which is used as the script’s exit value; - - o *list getenv(string envvar)*\ returns the value of environment variable *envvar* in a list containing two elements: - if the first element (\[0\]) is *"1"* then the environment variable was defined; - environment variables are of the form *variable=value*. If element *\[0\]* is *"1"* then the returned list’s second element \[1\] holds the *value* part of the environment variable, which is empty if the environment variable is merely defined; - - o *int getpid()*\ returns the process-id of the icmake byte code interpreter **icm-exec**; - - o *int putenv(string envvar)*\ adds or modifies *envvar* to the current **icmake**-script environment. Use the format: *"VAR=value"*. Use *"VAR"* to remove *"VAR"* from the environment. The function returns 0 unless *envvar* is empty, in which case 1 is returned; - - o *int system(\[int check,\] string command)*\ executes *command* using the [**system**(3)](/system/3.md) function. The first argument is optional: if omitted and calling the [**system**(3)](/system/3.md) function does not return 0 then the **icmake**-script ends with exit value 1; by specifying *P\_NOCHECK* **icmake**’s *system* function won’t terminate the script but returns the return value of the [**system**(3)](/system/3.md) function (normally the executed command’s exit value). The string *command* may use redirection and/or piping. ## USER DEFINED FUNCTIONS In addition to *main* additional functions can be defined. Once defined, they can be called. Forward referencing of either variables or functions is not supported, but calling functions recursively is. As function declarations are not supported indirect recursion cannot be used. Function overloading (based on differently typed parameters) is supported. User-defined functions must have the following elements: - o The function’s return type, which must be *void, int, string* or *list*. There is no default type; - - o The function’s name, e.g., *compile*; - - o A parameter list, defining zero or more comma-separated parameters. The parameters themselves consist of a type name (*int,* *string*, or *list*) followed by the parameter’s identifier. E.g., *(string outfile, string source)*; - - o A *body* surrounded by a pair of curly braces (*{* and *}*). Function bodies may contain variable definitions (optionally initialized at their definitions). Variable definitions start with a type name, followed by one or more comma separated and optionally initialized variable identifiers. If a variable is not explicitly initialized it is initialized by default: *int* variables are initialized to 0, *string* variables are initialized to empty strings (*""*) and *list* variables are initialized to empty lists. Function bodies may also contain zero or more statements (cf. section **FLOW CONTROL**). Note that variables may be defined (and optionally initialized) anywhere inside functions where expression statements can be used, and also in the condition sections of *if, for,* and *while* statements and in the initialization sections of *if* andd *for* statements. ## EXAMPLE In the following example all **C++** source files in the current directory are compiled unless their object files are more recent. The main function creates a list of source files and then passes each of them to a function *inspect*. That function inspects whether the source file is younger than its object file, and if so it calls *compile*. The function *compile* uses *exec* to call the compiler. If a compilation fails the script stops so the error can be repaired. ``` void compile(string src) { exec("g++ -c " + src); // compile ’src’ } void inspect(string src) { // get the obj-file’s name: // only compile if necessary if (src younger change_ext(src, ".o")) compile(src); } int main() { // find all .cc source files list sources = makelist("*.cc"); for ( // visit all source files int idx = 0, end = listlen(sources); idx != end; ++idx ) inspect(sources[idx]); // compile if needed } ``` ## SEE ALSO [**icmake**(1)](/icmake/1.md), [**icmbuild**(1)](/icmbuild/1.md), [**icmconf**(7)](/icmconf/7.md), [**icmstart**(1)](/icmstart/1.md), [**icmstart.rc**(7)](/icmstart.rc/7.md) ## BUGS Standard comment starting on lines containing preprocessor directives may not extend over multiple lines. Path names containing blanks are not supported. ## COPYRIGHT This is free software, distributed under the terms of the GNU General Public License (GPL). ## AUTHOR Frank B. Brokken (**f.b.brokken@rug.nl**).