Jump to:  OMake Home • Guide Home • Guide (single-page) • Contents (short) • Contents (long)
Index:  All • Variables • Functions • Objects • Targets • Options

Chapter 9  Base library

9.1  Builtin variables

OMAKE_VERSION

Version of OMake.

STDLIB

The directory where the OMake standard library files reside. At startup, the default value is determined as follows.

The current default value may be accessed by running omake --version

OMAKEPATH

An array of directories specifying the lookup path for the include and open directives (see Section 4.8). The default value is an array of two elements — . and $(STDLIB).

OSTYPE

Set to the machine architecture omake is running on. Possible values are Unix (for all Unix versions, including Linux and Mac OS X), Win32 (for MS-Windows, OMake compiled with MSVC++ or Mingw), and Cygwin (for MS-Windows, OMake compiled with Cygwin).

SYSNAME

The name of the operating system for the current machine.

NODENAME

The hostname of the current machine.

OS_VERSION

The operating system release.

MACHINE

The machine architecture, e.g. i386, sparc, etc.

HOST

Same as NODENAME.

USER

The login name of the user executing the process.

HOME

The home directory of the user executing the process.

PID

The OMake process id.

TARGETS

The command-line target strings. For example, if OMake is invoked with the following command line,

      omake CFLAGS=1 foo bar.c

then TARGETS is defined as foo bar.c.

BUILD_SUMMARY

The BUILD_SUMMARY variable refers to the file that omake uses to summarize a build (the message that is printed at the very end of a build). The file is empty when the build starts. If you wish to add additional messages to the build summary, you can edit/modify this file during the build.

For example, if you want to point out that some action was taken, you can append a message to the build summary.

   foo: boo
       echo "The file foo was built" >> $(BUILD_SUMMARY)
       ...build foo...
VERBOSE

Whether certain commands should be verbose. A boolean flag that is false by default and is set to true when OMake is invoked with the --verbose option.

9.2  Logic, Boolean functions, and control flow

Boolean values in omake are represented by case-insensitive strings. The false value can be represented by the strings false, no, nil, undefined or 0, and everything else is true.

9.2.1  not

   $(not e) : String
      e : String

The not function negates a Boolean value.

For example, $(not false) expands to the string true, and $(not hello world) expands to false.

9.2.2  equal

   $(equal e1, e2) : String
      e1 : String
      e2 : String

The equal function tests for equality of two values.

For example $(equal a, b) expands to false, and $(equal hello world, hello world) expands to true.

9.2.3  and

    $(and e1, ..., en) : String
       e1, ..., en: Sequence

The and function evaluates to the conjunction of its arguments.

For example, in the following code, X is true, and Y is false.

    A = a
    B = b
    X = $(and $(equal $(A), a) true $(equal $(B), b))
    Y = $(and $(equal $(A), a) true $(equal $(A), $(B)))

9.2.4  or

   $(or e1, ..., en) : String
      e1, ..., en: String Sequence

The or function evaluates to the disjunction of its arguments.

For example, in the following code, X is true, and Y is false.

    A = a
    B = b
    X = $(or $(equal $(A), a) false $(equal $(A), $(B)))
    Y = $(or $(equal $(A), $(B)) $(equal $(A), b))

9.2.5  if

    $(if e1, e2[, e3]) : value
       e1 : String
       e2, e3 : value

The if function represents a conditional based on a Boolean value. For example $(if $(equal a, b), c, d) evaluates to d.

Conditionals may also be declared with an alternate syntax.

   if e1
      body1
   elseif e2
      body2
   ...
   else
      bodyn

If the expression e1 is not false, then the expressions in body1 are evaluated and the result is returned as the value of the conditional. Otherwise, if e1 evaluates to false, the evaluation continues with the e2 expression. If none of the conditional expressions is true, then the expressions in bodyn are evaluated and the result is returned as the value of the conditional.

There can be any number of elseif clauses; the else clause is optional.

Note that each branch of the conditional defines its own scope, so variables defined in the branches are normally not visible outside the conditional. The export command may be used to export the variables defined in a scope. For example, the following expression represents a common idiom for defining the C compiler configuration.

   if $(equal $(OSTYPE), Win32)
      CC = cl
      CFLAGS += /DWIN32
      export
   else
      CC = gcc
      CFLAGS += -g -O2
      export

9.2.6  switch, match

The switch and match functions perform pattern matching.

$(switch <arg>, <pattern_1>, <value_1>, ..., <pattern_n>, <value_n>) $(match <arg>, <pattern_1>, <value_1>, ..., <pattern_n>, <value_n>)

The number of <pattern>/<value> pairs is arbitrary. They strictly alternate; the total number of arguments to <match> must be odd.

The <arg> is evaluated to a string, and compared with <pattern_1>. If it matches, the result of the expression is <value_1>. Otherwise evaluation continues with the remaining patterns until a match is found. If no pattern matches, the value is the empty string.

The switch function uses string comparison to compare the argument with the patterns. For example, the following expression defines the FILE variable to be either foo, bar, or the empty string, depending on the value of the OSTYPE variable.

    FILE = $(switch $(OSTYPE), Win32, foo, Unix, bar)

The match function uses regular expression patterns (see the grep function). If a match is found, the variables $1, $2, ... are bound to the substrings matched between \( and \) delimiters. The $0 variable contains the entire match, and $* is an array of the matched substrings. to the matched substrings.

    FILE = $(match foo_xyz/bar.a, foo_\\\(.*\\\)/\\\(.*\\\)\.a, foo_$2/$1.o)

The switch and match functions also have an alternate (more usable) form.

   match e
   case pattern1
      body1
   case pattern2
      body2
   ...
   default
      bodyd

If the value of expression e matches pattern_i and no previous pattern, then body_i is evaluated and returned as the result of the match. The switch function uses string comparison; the match function uses regular expression matching.

   match $(FILE)
   case $".*\(\.[^\/.]*\)"
      println(The string $(FILE) has suffix $1)
   default
      println(The string $(FILE) has no suffix)

9.2.7  try

   try
      try-body
   catch class1(v1)
      catch-body
   when expr
      when-body
   ...
   finally
      finally-body

The try form is used for exception handling. First, the expressions in the try-body are evaluated.

If evaluation results in a value v without raising an exception, then the expressions in the finally-body are evaluated and the value v is returned as the result.

If evaluation of the try-body results in a exception object obj, the catch clauses are examined in order. When examining catch clause catch class(v), if the exception object obj is an instance of the class name class, the variable v is bound to the exception object, and the expressions in the catch-body are evaluated.

If a when clause is encountered while a catch body is being evaluated, the predicate expr is evaluated. If the result is true, evaluation continues with the expressions in the when-body. Otherwise, the next catch clause is considered for evaluation.

If evaluation of a catch-body or when-body completes successfully, returning a value v, without encountering another when clause, then the expressions in the finally-body are evaluated and the value v is returned as the result.

There can be any number of catch clauses; the finally clause is optional.

9.2.8  raise

   raise exn
      exn : Exception

The raise function raises an exception. The exn object can be any object. However, the normal convention is to raise an Exception object.

If the exception is never caught, the whole object will be verbosely printed in the error message. However, if the object is an Exception one and contains a message field, only that field will be included in the error message.

9.2.9  exit

   exit(code)
      code : Int

The exit function terminates omake abnormally.

$(exit <code>)

The exit function takes one integer argument, which is exit code. Non-zero values indicate abnormal termination.

9.2.10  defined

   $(defined sequence) : String
      sequence : Sequence

The defined function test whether all the variables in the sequence are currently defined. For example, the following code defines the X variable if it is not already defined.

    if $(not $(defined X))
       X = a b c
       export

It is acceptable to use qualified names.

    $(defined X.a.b)
    $(defined public.X)

9.2.11  defined-env

   $(defined-env sequence) : String
      sequence : String

The defined-env function tests whether a variable is defined as part of the process environment.

For example, the following code adds the -g compile option if the environment variable DEBUG is defined.

if $(defined-env DEBUG)
    CFLAGS += -g
    export

9.2.12  getenv

   $(getenv name) : String
   $(getenv name, default) : String

The getenv function gets the value of a variable from the process environment. The function takes one or two arguments.

In the single argument form, an exception is raised if the variable variable is not defined in the environment. In the two-argument form, the second argument is returned as the result if the value is not defined.

For example, the following code defines the variable X to be a space-separated list of elements of the PATH environment variable if it is defined, and to /bin /usr/bin otherwise.

    X = $(split $(PATHSEP), $(getenv PATH, /bin:/usr/bin))

You may also use the alternate form.

     getenv(NAME)
         default

9.2.13  setenv

   setenv(name, value)
      name : String
      value : String

The setenv function sets the value of a variable in the process environment. Environment variables are scoped like normal variables.

9.2.14  unsetenv

   unsetenv(names)
      names : String Array

The unsetenv function removes some variable definitions from the process environment. Environment variables are scoped like normal variables.

9.2.15  get-registry

   get-registry(hkey, key, field) : String
   get-registry(hkey, key, field, default) : String
       hkey : String
       key : String
       field : String

The get-registry function retrieves a string value from the system registry on Win32. On other architectures, there is no registry.

The hive (I think that is the right word), indicates which part of the registry to use. It should be one of the following values.

Refer to the Microsoft documentation if you want to know what these mean.

The key is the field you want to get from the registry. It should have a form like A\B\C (if you use forward slashes, they will be converted to backslashes). The field is the sub-field of the key.

In the 4-argument form, the default is returned on failure. You may also use the alternate form.

    get-registry(hkey, key, field)
       default

9.2.16  getvar

   $(getvar name) : String

The getvar function gets the value of a variable.

An exception is raised if the variable variable is not defined.

For example, the following code defines X to be the string abc.

    NAME = foo
    foo_1 = abc
    X = $(getvar $(NAME)_1)

It is acceptable to use qualified names.

    $(getvar X.a.b)

9.2.17  setvar

   setvar(name, value)
      name : String
      value : String

The setvar function defines a new variable. For example, the following code defines the variable X to be the string abc.

   NAME = X
   setvar($(NAME), abc)

It is acceptable to use qualified names.

    setvar(public.X, abc)

9.3  Arrays and sequences

9.3.1  array

    $(array elements) : Array
       elements : Sequence

The array function creates an array from a sequence. If the <arg> is a string, the elements of the array are the whitespace-separated elements of the string, respecting quotes.

In addition, array variables can be declared as follows.

    A[] =
       <val1>
       ...
       <valn>

In this case, the elements of the array are exactly <val1>, ..., <valn>, and whitespace is preserved literally.

9.3.2  split

   $(split sep, elements) : Array
      sep : String
      elements : Sequence

The split function takes two arguments, a string of separators, and a string argument. The result is an array of elements determined by splitting the elements by all occurrence of the separator in the elements sequence.

For example, in the following code, the X variable is defined to be the array /bin /usr/bin /usr/local/bin.

    PATH = /bin:/usr/bin:/usr/local/bin
    X = $(split :, $(PATH))

The sep argument may be omitted. In this case split breaks its arguments along the white space. Quotations are not split.

9.3.3  concat

   $(concat sep, elements) : String
      sep : String
      elements : Sequence

The concat function takes two arguments, a separator string, and a sequence of elements. The result is a string formed by concatenating the elements, placing the separator between adjacent elements.

For example, in the following code, the X variable is defined to be the string foo_x_bar_x_baz.

    X = foo  bar     baz
    Y = $(concat _x_, $(X))

9.3.4  length

   $(length sequence) : Int
      sequence : Sequence

The length function returns the number of elements in its argument.

For example, the expression $(length a b "c d") evaluates to 3.

9.3.5  nth

   $(nth i, sequence) : value
      i : Int
      sequence : Sequence
   raises RuntimeException

The nth function returns the nth element of its argument, treated as a list. Counting starts at 0. An exception is raised if the index is not in bounds.

For example, the expression $(nth 1, a "b c" d) evaluates to "b c".

9.3.6  replace-nth

   $(replace-nth i, sequence, x) : value
      i : Int
      sequence : Sequence
      x : value
   raises RuntimeException

The replace-nth function replaces the nth element of its argument with a new value x. Counting starts at 0. An exception is raised if the index is not in bounds.

For example, the expression $(replace-nth 1, a "b c" d, x) evaluates to a x d.

9.3.7  nth-hd

   $(nth-hd i, sequence) : value
      i : Int
      sequence : Sequence
   raises RuntimeException

The nth-hd function returns the first i elements of the sequence. An exception is raised if the sequence is not at least i elements long.

For example, the expression $(nth-hd 2, a "b c" d) evaluates to a "b c".

9.3.8  nth-tl

   $(nth-tl i, sequence) : value
      i : Int
      sequence : Sequence
   raises RuntimeException

The nth-tl function skips i elements of the sequence and returns the rest. An exception is raised if the sequence is not at least i elements long.

For example, the expression $(nth-tl 1, a "b c" d) evaluates to "b c" d.

9.3.9  subrange

   $(subrange off, len, sequence) : value
      off : Int
      len : Int
      sequence : Sequence
   raises RuntimeException

The subrange function returns a subrange of the sequence. Counting starts at 0. An exception is raised if the specified range is not in bounds.

For example, the expression $(subrange 1, 2, a "b c" d e) evaluates to "b c" d.

9.3.10  rev

    $(rev sequence) : Sequence
       sequence : Sequence

The rev function returns the elements of a sequence in reverse order. For example, the expression $(rev a "b c" d) evaluates to d "b c" a.

9.3.11  join

   $(join sequence1, sequence2) : Sequence
      sequence1 : Sequence
      sequence2 : Sequence

The join function joins together the elements of the two sequences. For example, $(join a b c, .c .cpp .h) evaluates to a.c b.cpp c.h. If the two input sequences have different lengths, the remainder of the longer sequence is copied at the end of the output unmodified.

9.3.12  string

   $(string sequence) : String
      sequence : Sequence

The string function flattens a sequence into a single string. This is similar to the concat function, but the elements are separated by whitespace. The result is treated as a unit; whitespace is significant.

9.3.13  string-length

   $(string-length sequence) : Int
      sequence : Sequence

The string-lenght returns a length (number of characters) in its argument. If the argument is a sequence, it flattens it, so $(string-length sequence) is equivalent to $(string-length $(string sequence)).

9.3.14  string-escaped, ocaml-escaped, html-escaped, html-pre-escaped

9.3.15  c-escaped, id-escaped, sql-escaped, uri-escaped

   $(string-escaped sequence) : String Array
   $(ocaml-escaped sequence) : String Array
   $(html-escaped sequence) : String Array
   $(html-pre-escaped sequence) : String Array
   $(c-escaped sequence) : String Array
   $(id-escaped sequence) : StringArray
   $(sql-escaped sequence) : StringArray
   $(uri-escaped sequence) : StringArray
      sequence : Array

The string-escaped function converts each element of its argument to a string, escaping it, if it contains symbols that are special to OMake. The special characters include :()\,$'"# and whitespace. This function can be used in scanner rules to escape file names before printing then to stdout.

The ocaml-escaped function converts each element of its argument to a string, escaping characters that are special to OCaml.

The c-escaped function converts a string to a form that can be used as a string constant in C.

The id-escaped function turns a string into an identifier that may be used in OMake.

The html-escaped function turns a literal string into a form acceptable as HTML. The html-pre-escaped function is similar, but it does not translate newlines into <br>.

    println($(string $(string-escaped $"a b" $"y:z")))
    a\ b y\:z

9.3.16  hexify, unhexify

   $(hexify sequence) : sequence
       sequence : Sequence

The function hexify converts a string to a HEX ASCII representation. The inverse function is unhexify.

   osh> hexify($"Hello world")
   - : <array <data "48656c6c6f"> <data "776f726c64">>

9.3.17  decode-uri, encode-uri

    $(decode-uri sequence) : sequence
        sequence : Sequence

These two functions perform URI encoding, where special characters are represented by hexadecimal characters.

    osh> s = $(encode-uri $'a b~c')
    "a+b%7ec"
    osh> decode-uri($s)
    "a b~c"

9.3.18  quote

   $(quote sequence) : String
      sequence : Sequence

The quote function flattens a sequence into a single string and adds quotes around the string. Inner quotation symbols are escaped.

For example, the expression $(quote a "b c" d) evaluates to "a \"b c\" d", and $(quote abc) evaluates to "abc".

9.3.19  quote-argv

   $(quote-argv sequence) : String
      sequence : Sequence

The quote-argv function flattens a sequence into a single string, and adds quotes around the string. The quotation is formed so that a command-line parse can separate the string back into its components.

9.3.20  html-string

   $(html-string sequence) : String
      sequence : Sequence

The html-string function flattens a sequence into a single string, and escapes special HTML characters. This is similar to the concat function, but the elements are separated by whitespace. The result is treated as a unit; whitespace inside sequence elements is preserved literally.

9.3.21  addsuffix

   $(addsuffix suffix, sequence) : Array
      suffix : String
      sequence : Sequence

The addsuffix function adds a suffix to each component of sequence. The number of elements in the array is exactly the same as the number of elements in the sequence.

For example, $(addsuffix .c, a b "c d") evaluates to a.c b.c "c d".c.

9.3.22  mapsuffix

   $(mapsuffix suffix, sequence) : Array
      suffix : value
      sequence : Sequence

The mapsuffix function adds a suffix to each component of sequence. It is similar to addsuffix, but uses array concatenation instead of string concatenation. The number of elements in the array is twice the number of elements in the sequence.

For example, $(mapsuffix .c, a b "c d") evaluates to a .c b .c "c d" .c.

9.3.23  addsuffixes, addprefixes

   $(addsuffixes suffixes, sequence) : Array
      suffixes : Sequence
      sequence : Sequence
   $(addprefixes prefixes, sequence) : Array
      prefixes : Sequence
      sequence : Sequence

The addsuffixes function adds all suffixes in its first argument to each component of a sequence. If suffixes has n elements, and sequence has m elements, the the result has n * m elements.

For example, the $(addsuffixes .c .o, a b c) expressions evaluates to a.c a.o b.c b.o c.o c.a.

$(addprefixes prefixes, sequence) is roughly equivalent to $(addsuffixes sequence, prefixes).

9.3.24  removeprefix

   $(removeprefix prefix, sequence) : Array
      prefix : String
      sequence : Array

The removeprefix function removes a prefix from each component of a sequence.

9.3.25  removesuffix

   $(removesuffix sequence) : Array
      sequence : String

The removesuffix function removes the suffixes from each component of a sequence.

For example, $(removesuffix a.c b.foo "c d") expands to a b "c d".

9.3.26  replacesuffixes

   $(replacesuffixes old-suffixes, new-suffixes, sequence) : Array
      old-suffixes : Sequence
      new-suffixes : Sequence
      sequence : Sequence

The replacesuffixes function modifies the suffix of each component in sequence. The old-suffixes and new-suffixes sequences should have the same length.

For example, $(replacesuffixes .h .c, .o .o, a.c b.h c.z) expands to a.o b.o c.z.

9.3.27  addprefix

   $(addprefix prefix, sequence) : Array
      prefix : String
      sequence : Sequence

The addprefix function adds a prefix to each component of a sequence. The number of element in the result array is exactly the same as the number of elements in the argument sequence.

For example, $(addprefix foo/, a b "c d") evaluates to foo/a foo/b foo/"c d".

9.3.28  mapprefix

   $(mapprefix prefix, sequence) : Array
      prefix : String
      sequence : Sequence

The mapprefix function adds a prefix to each component of a sequence. It is similar to addprefix, but array concatenation is used instead of string concatenation. The result array contains twice as many elements as the argument sequence.

For example, $(mapprefix foo, a b "c d") expands to foo a foo b foo "c d".

9.3.29  add-wrapper

   $(add-wrapper prefix, suffix, sequence) : Array
      prefix : String
      suffix : String
      sequence : Sequence

The add-wrapper functions adds both a prefix and a suffix to each component of a sequence. For example, the expression $(add-wrapper dir/, .c, a b) evaluates to dir/a.c dir/b.c. String concatenation is used. The array result has the same number of elements as the argument sequence.

9.3.30  set

   $(set sequence) : Array
      sequence : Sequence

The set function sorts a set of string components, eliminating duplicates.

For example, $(set z y z "m n" w a) expands to "m n" a w y z.

9.3.31  mem

   $(mem elem, sequence) : Boolean
      elem : String
      sequence : Sequence

The mem function tests for membership in a sequence.

For example, $(mem "m n", y z "m n" w a) evaluates to true, while $(mem m n, y z "m n" w a) evaluates to false.

9.3.32  intersection

   $(intersection sequence1, sequence2) : Array
      sequence1 : Sequence
      sequence2 : Sequence

The intersection function takes two arguments, treats them as sets of strings, and computes their intersection. The order of the result is undefined, and it may contain duplicates. Use the set function to sort the result and eliminate duplicates in the result if desired.

For example, the expression $(intersection c a b a, b a) evaluates to a b a.

9.3.33  intersects

   $(intersects sequence1, sequence2) : Boolean
      sequence1 : Sequence
      sequence2 : Sequence

The intersects function tests whether two sets have a non-empty intersection. This is slightly more efficient than computing the intersection and testing whether it is empty.

For example, the expression $(intersects a b c, d c e) evaluates to true, and $(intersects a b c a, d e f) evaluates to false.

9.3.34  set-diff

   $(set-diff sequence1, sequence2) : Array
      sequence1 : Sequence
      sequence2 : Sequence

The set-diff function takes two arguments, treats them as sets of strings, and computes their difference (all the elements of the first set that are not present in the second one). The order of the result is undefined and it may contain duplicates. Use the set function to sort the result and eliminate duplicates in the result if desired.

For example, the expression $(set-diff c a b a e, b a) evaluates to c e.

9.3.35  filter

   $(filter patterns, sequence) : Array
      patterns : Sequence
      sequence : Sequence

The filter function picks elements from a sequence. The patterns is a non-empty sequence of patterns, each may contain one occurrence of the wildcard % character.

For example $(filter %.h %.o, a.c x.o b.h y.o "hello world".c) evaluates to x.o b.h y.o.

9.3.36  filter-out

   $(filter-out patterns, sequence) : Array
      patterns : Sequence
      sequence : Sequence

The filter-out function removes elements from a sequence. The patterns is a non-empty sequence of patterns, each may contain one occurrence of the wildcard % character.

For example $(filter-out %.c %.h, a.c x.o b.h y.o "hello world".c) evaluates to x.o y.o.

9.3.37  capitalize

   $(capitalize sequence) : Array
      sequence : Sequence

The capitalize function capitalizes each word in a sequence. For example, $(capitalize through the looking Glass) evaluates to Through The Looking Glass.

9.3.38  uncapitalize

   $(uncapitalize sequence) : Array
      sequence : Sequence

The uncapitalize function uncapitalizes each word in its argument.

For example, $(uncapitalize through the looking Glass) evaluates to through the looking glass.

9.3.39  uppercase

   $(uppercase sequence) : Array
      sequence : Sequence

The uppercase function converts each word in a sequence to uppercase. For example, $(uppercase through the looking Glass) evaluates to THROUGH THE LOOKING GLASS.

9.3.40  lowercase

   $(lowercase sequence) : Array
      sequence : Sequence

The lowercase function reduces each word in its argument to lowercase.

For example, $(lowercase through tHe looking Glass) evaluates to through the looking glass.

9.3.41  system

   system(s)
      s : Sequence

The system function is used to evaluate a shell expression. This function is used internally by omake to evaluate shell commands.

For example, the following program is equivalent to the expression system(ls foo).

   ls foo

9.3.42  shell

   $(shell command) : Array
   $(shella command) : Array
   $(shell-code command) : Int
      command : Sequence

The shell function evaluates a command using the command shell, and returns the whitespace-separated words of the standard output as the result.

The shella function acts similarly, but it returns the lines as separate items in the array.

The shell-code function returns the exit code. The output is not diverted.

For example, if the current directory contains the files OMakeroot, OMakefile, and hello.c, then $(shell ls) evaluates to hello.c OMakefile OMakeroot (on a Unix system).

9.3.43  export

The export function allows one to capture the current environment in a variable.

For example, the following code:

A = 1
B = 1
C = 1
SAVE_ENV = $(export A B)
A = 2
B = 2
C = 2
export($(SAVE_ENV))
println($A $B $C)

will print 1 1 2.

The arguments to this function are interpreted the exact same way as the arguments to the export special form (see Section 6.3).

9.3.44  while

   while <test>
      <body>

–or–

    while <test>
    case <test1>
       <body1>
    ...
    case <testn>
       <bodyn>
    default
       <bodyd>

The loop is executed while the test is true. In the first form, the <body> is executed on every loop iteration. In the second form, the body <bodyI> is selected, as the first case where the test <testI> is true. If none apply, the optional default case is evaluated. If no cases are true, the loop exits. The environment is automatically exported.

Examples.

Iterate for i from 0 to 9.

    i = 0
    while $(lt $i, 10)
       echo $i
       i = $(add $i, 1)

The following example is equivalent.

   i = 0
   while true
   case $(lt $i, 10)
      echo $i
      i = $(add $i, 1)

The following example is similar, but some special cases are printed. value is printed.

    i = 0
    while $(lt $i, 10)
    case $(equal $i, 0)
       echo zero
       i = $(add $i, 1)
    case $(equal $i, 1)
       echo one
       i = $(add $i, 1)
    default
       echo $i
       i = $(add $i, 1)

The break function can be used to break out of the while loop early.

9.3.45  break

   break

Terminate execution of the innermost loop, returning the current state.

9.3.46  random, random-init

    random-init(i)
        i : Int
    random() : Int

Produce a random number. The numbers are pseudo-random, and are not cryptographically secure.

The generator is initialized from semi-random system data. Subsequent runs should produce different results. The rando-init function can be used to return the generator to a known state.

9.4  Arithmetic

9.4.1  int

The int function can be used to create integers. It returns an Int object.

$(int 17).

9.4.2  float

The float function can be used to create floating-point numbers. It returns a Float object.

$(float 3.1415926).

9.4.3  Basic arithmetic

The following functions can be used to perform basic arithmetic.

9.4.4  Comparisons

The following functions can be used to perform numerical comparisons.

9.5  First-class functions

9.5.1  fun

The fun form introduces anonymous functions.

$(fun <v1>, ..., <vn> => <body>)

The last argument is the body of the function. The other arguments are the parameter names.

The three following definitions are equivalent.

    F(X, Y) =
       return($(addsuffix $(Y), $(X)))

    F = $(fun X, Y => $(addsuffix $(Y), $(X)))

    F =
       fun(X, Y) =>
          value $(addsuffix $(Y), $(X))

9.5.2  apply

The apply operator is used to apply a function.

$(apply <fun>, <args>)

Suppose we have the following function definition.

    F(X, Y) =
       return($(addsuffix $(Y), $(X)))

The the two expressions below are equivalent.

    X = F(a b c, .c)
    X = $(apply $(F), a b c, .c)

The apply form can also be used for partial applications, where a function is passed fewer arguments than it expects. The result is a function that takes the remaining arguments, and calls the function with the full set of arguments.

    add2(i, j) =
       add($i, $j)
    succ = $(apply $(add2), 1)
    i = $(succ 5)   # Computes 1+5

9.5.3  applya

The applya operator is used to apply a function to an array of arguments.

$(applya <fun>, <args>)

For example, in the following program, the value of Z is file.c.

    F(X, Y) =
       return($(addsuffix $(Y), $(X)))
    args[] =
       file
       .c
    Z = $(applya $(F), $(args))

The applya form can also be used for partial applications.

9.5.4  create-map, create-lazy-map

The create-map is a simplified form for creating Map objects. The create-map function takes an even number of arguments that specify key/value pairs. For example, the following values are equivalent.

    X = $(create-map name1, xxx, name2, yyy)

    X. =
        extends $(Map)
        $|name1| = xxx
        $|name2| = yyy

The create-lazy-map function is similar, but the values are computed lazily. The following two definitions are equivalent.

    Y = $(create-lazy-map name1, $(xxx), name2, $(yyy))

    Y. =
        extends $(Map)
        $|name1| = $`(xxx)
        $|name2| = $`(yyy)

The create-lazy-map function is used in rule construction.

9.6  Iteration and mapping

9.6.1  foreach

The foreach function maps a function over a sequence.

    $(foreach <fun>, <args>)

    foreach(<var> => ..., <args>)
       <body>

For example, the following program defines the variable X as an array a.c b.c c.c.

    X =
       foreach(x => ..., a b c)
          value $(x).c

    # Equivalent expression
    X = $(foreach $(fun x => ..., $(x).c), a b c)

There is also an abbreviated syntax.

The export form can also be used in a foreach body. The final value of X is a.c b.c c.c.

    X =
    foreach(x => ..., a b c)
       X += $(x).c
       export

The break function can be used to break out of the loop early.

9.7  Boolean tests

9.7.1  sequence-forall

The forall function tests whether a predicate holds for each element of a sequence.

    $(sequence-forall <fun>, <args>)

    sequence-forall(<var> => ..., <args>)
       <body>

9.7.2  sequence-exists

The exists function tests whether a predicate holds for some element of a sequence.

    $(sequence-exists <fun>, <args>)

    sequence-exists(<var> => ..., <args>)
       <body>

9.7.3  sequence-sort

The sort function sorts the elements in an array, given a comparison function. Given two elements (x, y), the comparison should return a negative number if x < y; a positive number if x > y; and 0 if x = y.

    $(sequence-sort <fun>, <args>)

    sort(<var>, <var> => ..., <args>)
       <body>

9.7.4  compare

The compare function compares two values (x, y) generically returning a negative number if x < y; a positive number if x > y; and 0 if x = y.

    $(compare x, y) : Int
Jump to:  OMake Home • Guide Home • Guide (single-page) • Contents (short) • Contents (long)
Index:  All • Variables • Functions • Objects • Targets • Options