diff --git a/doc/config.ld b/doc/config.ld index 6d722725..8ce3e9a8 100644 --- a/doc/config.ld +++ b/doc/config.ld @@ -1,5 +1,5 @@ project = 'Penlight' -description = 'Penlight Lua Libraries 1.2.1' +description = 'Penlight Lua Libraries 1.3.1' full_description = 'The documentation is available @{01-introduction.md|here}.' title = 'Penlight Documentation' dir = 'api' diff --git a/doc/manual/01-introduction.md b/doc/manual/01-introduction.md index 8d5efd28..a8bf26a9 100644 --- a/doc/manual/01-introduction.md +++ b/doc/manual/01-introduction.md @@ -31,9 +31,6 @@ useful message. This is more appropriate behaviour for a _script_ than providing a stack trace. (However, this default can be changed.) The lexer functions always throw errors, to simplify coding, and so should be wrapped in `pcall`. -By default, the error stacktrace starts with your code, since you are not usually -interested in the internal details of the library. ?? - If you are used to Python conventions, please note that all indices consistently start at 1. @@ -50,14 +47,6 @@ either [alien](http://alien.luaforge.net/) or be using [LuaJIT](http://luajit.org) as well. (The fallback is to call the equivalent shell commands.) -Some of the examples in this guide were created using -[ilua](http://lua-users.org/wiki/InteractiveLua), which doesn't require '=' to -print out expressions, and will attempt to print out table results as nicely as -possible. This is also available under Lua for Windows, as a library, so the -command `lua -lilua -s` will work (the s option switches off 'strict' variable -checking, which is annoying and conflicts with the use of `_DEBUG` in some of -these libraries. - ### To Inject or not to Inject? It was realized a long time ago that large programs needed a way to keep names @@ -111,16 +100,12 @@ make Penlight available within a module: return M -The default is to put Penlight into `_ENV`, which has the unintended effect of +The default is to put Penlight into `\_ENV`, which has the unintended effect of making it available from the module (much as `module(...,package.seeall)` does). To satisfy both convenience and safety, you may pass `true` to this function, and -then the _module_ `M` is not the same as `_ENV`, but only contains the exported +then the _module_ `M` is not the same as `\_ENV`, but only contains the exported functions. -With Penlight after 0.9, please note that `require 'pl.utils'` no longer implies -that a global table `pl.utils` exists, since these new modules are no longer -created with `module()`. - Otherwise, Penlight will _not_ bring in functions into the global table, or clobber standard tables like 'io'. require('pl') will bring tables like 'utils','tablex',etc into the global table _if they are used_. This @@ -206,7 +191,7 @@ than merely returning a `nil` that will cause problems later. Many functions in Penlight themselves take function arguments, like `map` which applies a function to a list, element by element. You can use existing functions, like `math.max`, anonymous functions (like `function(x,y) return x > y -end`), or operations by name (e.g '*' or '..'). The module `pl.operator` exports +end` ), or operations by name (e.g '*' or '..'). The module `pl.operator` exports all the standard Lua operations, like the Python module of the same name. Penlight allows these to be referred to by name, so `operator.gt` can be more concisely expressed as '>'. @@ -217,7 +202,7 @@ have `ls:filter('>',0)`, which is a shortcut for Finally, `pl.func` supports _placeholder expressions_ in the Boost lambda style, so that an anonymous function to multiply the two arguments can be expressed as -`_1*_2`. +`\_1*\_2`. To use them directly, note that _all_ function arguments in Penlight go through `utils.function_arg`. `pl.func` registers itself with this function, so that you @@ -228,10 +213,9 @@ can directly use placeholder expressions with standard methods: {11,21,31} Another option for short anonymous functions is provided by -`utils.string_lambda`; since 0.9 you have to explicitly ask for this feature: +`utils.string_lambda`; this is invoked automatically: - > L = require 'pl.utils'.string_lambda - > = List{10,20,30}:map (L'|x| x + 1') + > = List{10,20,30}:map '|x| x + 1' {11,21,31} ### Pros and Cons of Loopless Programming @@ -254,7 +238,7 @@ then you have failed to express yourself clearly. Similarly, `ls:filter('>',0)` will give you all the values in a list greater than zero. (Of course, if you don't feel like using `List`, or have non-list-like tables, then `pl.tablex` offers the same facilities. In fact, the `List` methods are implemented using -`tablex' functions.) +`tablex` functions.) A common observation is that loopless programming is less efficient, particularly in the way it uses memory. `ls1:map2('*',ls2):reduce '+'` will give you the dot @@ -282,10 +266,9 @@ also takes a file object parameter, just like the C function.) Splitting a string using a delimiter is a fairly common operation, hence `split`. -Utility functions like `is_callable` and `is_type` help with identifying what -kind of animal you are dealing with. Obviously, a function is callable, but an -object can be callable as well if it has overriden the `__call` metamethod. The -Lua `type` function handles the basic types, but can't distinguish between +Utility functions like `is_type` help with identifying what +kind of animal you are dealing with. +The Lua `type` function handles the basic types, but can't distinguish between different kinds of objects, which are all tables. So `is_type` handles both cases, like `is_type(s,"string")` and `is_type(ls,List)`. @@ -339,11 +322,9 @@ whether the source is a binary chunk or text code (default is 'bt') Using `utils.load` should reduce the need to call the deprecated function `setfenv`, and make your Lua 5.1 code 5.2-friendly. -Currently, the `utils` module does define a global `getfenv` and `setfenv` for -Lua 5.2, based on code by Sergey Rozhenko. Note that these functions can fail -for functions which don't access any globals. (whether it's wise to directly -inject these functions into global or not, I'll leave for a later version to -decide) +The `utils` module exports `getfenv` and `setfenv` for +Lua 5.2 as well, based on code by Sergey Rozhenko. Note that these functions can fail +for functions which don't access any globals. ### Application Support @@ -361,7 +342,7 @@ integer. Or you may specify upfront that some flags have associated values, and then the values will follow the flag. > require 'pl' - > flags,args = utils.parse_args({'-o','fred','-n10','fred.txt'},{o=true}) + > flags,args = app.parse_args({'-o','fred','-n10','fred.txt'},{o=true}) > pretty.dump(flags) {o='fred',n='10'} @@ -380,10 +361,12 @@ private data, based on the script name. For example, `app.appfile "test.txt"` from a script called `testapp.lua` produces the following file on my Windows machine: + @plain C:\Documents and Settings\SJDonova\.testapp\test.txt and the equivalent on my Linux machine: + @plain /home/sdonovan/.testapp/test.txt If `.testapp` does not exist, it will be created. @@ -400,7 +383,7 @@ Lua is similar to JavaScript in that the concept of class is not directly supported by the language. In fact, Lua has a very general mechanism for extending the behaviour of tables which makes it straightforward to implement classes. A table's behaviour is controlled by its metatable. If that metatable -has a `__index` function or table, this will handle looking up anything which is +has a `\_\_index` function or table, this will handle looking up anything which is not found in the original table. A class is just a table with an `__index` key pointing to itself. Creating an object involves making a table and setting its metatable to the class; then when handling `obj.fun`, Lua first looks up `fun` in @@ -459,7 +442,7 @@ syntactic sugar, it is straightforward to implement classic object orientation. > = leo:is_a(Cat) true -All Animal does is define `__tostring`, which Lua will use whenever a string +All Animal does is define `\_\_tostring`, which Lua will use whenever a string representation is needed of the object. In turn, this relies on `speak`, which is not defined. So it's what C++ people would call an abstract base class; the specific derived classes like Dog define `speak`. Please note that _if_ derived @@ -536,7 +519,7 @@ multiple values) and `OrderedMap` (where the order of insertion is remembered.). There is nothing special about these classes and you may inherit from them. A powerful thing about dynamic languages is that you can redefine existing classes -and functions, which is often called 'monkey patching`. It's entertaining and convenient, +and functions, which is often called 'monkey patching' It's entertaining and convenient, but ultimately anti-social; you may modify `List` but then any other modules using this _shared_ resource can no longer be sure about its behaviour. (This is why you must say `stringx.import()` explicitly if you want the extended string methods - it @@ -627,7 +610,7 @@ when reading `mp.a`, first a check for an explicit _getter_ `get_a` and then onl look for `_a`. Simularly, writing `mp.a` causes the _setter_ `set_a` to be used. This is cool behaviour, but like much Lua metaprogramming, it is not free. Method -lookup on such objects goes through `__index` as before, but now `__index` is a +lookup on such objects goes through `\_\_index` as before, but now `\_\_index` is a function which has to explicitly look up methods in the class, before doing any property indexing, which is not going to be as fast as field lookup. If however, your accessors actually do non-trivial things, then the extra overhead could be @@ -635,5 +618,4 @@ worth it. This is not really intended for _access control_ because external code can write to `mp._a` directly. It is possible to have this kind of control in Lua, but it -again comes with run-time costs, and in this case a simple audit of code will -reveal any naughty use of 'protected' fields. +again comes with run-time costs. diff --git a/doc/manual/02-arrays.md b/doc/manual/02-arrays.md index 918d7a5d..9ee292f3 100644 --- a/doc/manual/02-arrays.md +++ b/doc/manual/02-arrays.md @@ -227,7 +227,7 @@ are fruits and colours but not both?' [blue,green,apple,red,banana] Adding elements to a set is simply `fruit['peach'] = true` and removing is -`fruit['apple'] = nil` . To make this simplicity properly, the `Set` class has no +`fruit['apple'] = nil` . To make this simplicity work properly, the `Set` class has no methods - either you use the operator forms or explicitly use `Set.intersect` etc. In this way we avoid the ambiguity that plagues `Map`. diff --git a/doc/manual/03-strings.md b/doc/manual/03-strings.md index a408fc9e..377cf013 100644 --- a/doc/manual/03-strings.md +++ b/doc/manual/03-strings.md @@ -40,7 +40,7 @@ easily at hand. Note that can be injected into the `string` table if you use is preferrable. This is the recommended practice when writing modules for consumption by other people, since it is bad manners to change the global state of the rest of the system. Magic may be used for convenience, but there is always -a cost. +a price. ### String Templates @@ -116,6 +116,9 @@ will also expand `$` variables using named fields: > = '$animal[$num]' % {animal='dog',num=1} dog[1] +As with `stringx.import` you have to do this explicitly, since all strings share the same +metatable. But in your own scripts you can feel free to do this. + ### Another Style of Template A new module is `template`, which is a version of Rici Lake's [Lua @@ -149,8 +152,8 @@ and we get There is a single function, `template.substitute` which is passed a template string and an environment table. This table may contain some special fields, -like `_parent` which can be set to a table representing a 'fallback' environment -in case a symbol was not found. `_brackets` is usually '()' and `_escape` is +like `\_parent` which can be set to a table representing a 'fallback' environment +in case a symbol was not found. `\_brackets` is usually '()' and `\_escape` is usually '#' but it's sometimes necessary to redefine these if the defaults interfere with the target language - for instance, `$(V)` has another meaning in Make, and `#` means a preprocessor line in C/C++. diff --git a/doc/manual/06-data.md b/doc/manual/06-data.md index 3ad6f87e..8c759d78 100644 --- a/doc/manual/06-data.md +++ b/doc/manual/06-data.md @@ -21,7 +21,7 @@ Here is a simple Lua implementation: -- property file parsing with Lua string patterns props = [] for line in io.lines() do - if line:find('#,1,true) ~= 1 and not line:find('^%s*$') then + if line:find('#',1,true) ~= 1 and not line:find('^%s*$') then local var,value = line:match('([^=]+)=(.*)') props[var] = value end @@ -373,8 +373,7 @@ the actual iterator function which a query generates and dynamically compiles. B using code generation, we can get pretty much optimal performance out of arbitrary queries. - > lua -lpl -e "_DEBUG=true" -e "data.filter 'x,y where x > 4 sort by x'" < -test.txt + > lua -lpl -e "_DEBUG=true" -e "data.filter 'x,y where x > 4 sort by x'" < test.txt return function (t) local i = 0 local v @@ -622,7 +621,7 @@ read a configuration from a string, use `stringio.open`. Although Lua's string pattern matching is very powerful, there are times when something more powerful is needed. `pl.lexer.scan` provides lexical scanners -which _tokenizes_ a string, classifying tokens into numbers, strings, etc. +which _tokenize_ a string, classifying tokens into numbers, strings, etc. > lua -lpl Lua 5.1.4 Copyright (C) 1994-2008 Lua.org, PUC-Rio diff --git a/doc/manual/07-functional.md b/doc/manual/07-functional.md index aad7a3fb..5921a3d5 100644 --- a/doc/manual/07-functional.md +++ b/doc/manual/07-functional.md @@ -354,22 +354,23 @@ values of a sequence or as a callback. Often useful functions have the wrong number of arguments. So there is a need to construct a function of one argument from one of two arguments, _binding_ the extra argument to a given value. -_currying_ takes a function of n arguments and returns a function of n-1 +_partial application_ takes a function of n arguments and returns a function of n-1 arguments where the first argument is bound to some value: - > p2 = func.curry(print,'start>') + > p2 = func.bind1(print,'start>') > p2('hello',2) start> hello 2 > ops = require 'pl.operator' - > = tablex.filter({1,-2,10,-1,2},curry(ops.gt,0)) + > = tablex.filter({1,-2,10,-1,2},bind1(ops.gt,0)) {-2,-1} - > tablex.filter({1,-2,10,-1,2},curry(ops.le,0)) + > tablex.filter({1,-2,10,-1,2},bind1(ops.le,0)) {1,10,2} -The last example unfortunately reads backwards, because `curry` alway binds the -first argument! +The last example unfortunately reads backwards, because `bind1` alway binds the +first argument! Also unfortunately, in my youth I confused 'currying' with +'partial application', so the old name for `bind1` is `curry` - this alias still exists. -Currying is a specialized form of function argument binding. Here is another way +This is a specialized form of function argument binding. Here is another way to say the `print` example: > p2 = func.bind(print,'start>',func._1,func._2) @@ -387,7 +388,6 @@ way around: > tablex.filter({1,-2,10,-1,2},bind(ops.gt, _1, 0)) {1,10,2} - `tablex.merge` does a general merge of two tables. This example shows the usefulness of binding the last argument of a function. @@ -400,7 +400,7 @@ usefulness of binding the last argument of a function. > = union(S1,S2) {mary=24,jane=31,john=27,jones=50} -When using `bind` to curry `print`, we got a function of precisely two arguments, +When using `bind` with `print`, we got a function of precisely two arguments, whereas we really want our function to use varargs like `print`. This is the role of `_0`: diff --git a/doc/manual/08-additional.md b/doc/manual/08-additional.md index 268f5e16..c445e5c3 100644 --- a/doc/manual/08-additional.md +++ b/doc/manual/08-additional.md @@ -164,8 +164,8 @@ command-line parsing easier and intuitive. It implements the standard GNU style, i.e. short flags with one letter start with '-', and there may be an additional long flag which starts with '--'. Generally options which take an argument expect to find it as the next parameter (e.g. 'gcc test.c -o test') but single short -options taking a numerical parameter can dispense with the space (e.g. 'head -n4 -test.c') +options taking a value can dispense with the space (e.g. 'head -n4 +test.c' or `gcc -I/usr/include/lua/5.1 ...`) As far as possible, Lapp will convert parameters into their equivalent Lua types, i.e. convert numbers and convert filenames into file objects. If any conversion @@ -436,8 +436,10 @@ argument. If you'd like to use a multi-letter 'short' parameter you need to set the `lapp.slack` variable to `true`. -In the following example we also see how default`false` and default`true` flags can be used -and how to overwrite the default `-h` help flag (`--help` still works fine). + +In the following example we also see how default `false` and default `true` flags can be used +and how to overwrite the default `-h` help flag (`--help` still works fine) - this applies +to non-slack mode as well. -- Parsing the command line ---------------------------------------------------- -- test.lua diff --git a/lua/pl/func.lua b/lua/pl/func.lua index 60e8ccb0..e16613ec 100644 --- a/lua/pl/func.lua +++ b/lua/pl/func.lua @@ -311,13 +311,13 @@ end utils.add_function_factory(_PEMT,func.I) --- bind the first parameter of the function to a value. --- @class function --- @name func.curry +-- @function func.bind1 -- @param fn a function of one or more arguments -- @param p a value -- @return a function of one less argument --- @usage (curry(math.max,10))(20) == math.max(10,20) -func.curry = utils.bind1 +-- @usage (bind1(math.max,10))(20) == math.max(10,20) +func.bind1 = utils.bind1 +func.curry = func.bind1 --- create a function which chains two functions. -- @param f a function of at least one argument diff --git a/lua/pl/init.lua b/lua/pl/init.lua index 656046fc..c27a890b 100644 --- a/lua/pl/init.lua +++ b/lua/pl/init.lua @@ -4,7 +4,7 @@ -- (e.g. `utils.split`) -- then that module is dynamically loaded. The submodules are all brought into -- the global space. ---Updated to use pl.import_into +--Updated to use @{pl.import_into} -- @module pl require'pl.import_into'(_G) diff --git a/lua/pl/utils.lua b/lua/pl/utils.lua index 90ac0754..515ca1c7 100644 --- a/lua/pl/utils.lua +++ b/lua/pl/utils.lua @@ -355,7 +355,7 @@ end -- @param p a value -- @return a function such that f(x) is fn(p,x) -- @raise same as @{function_arg} --- @see pl.func.curry +-- @see func.bind1 function utils.bind1 (fn,p) fn = utils.function_arg(1,fn) return function(...) return fn(p,...) end diff --git a/run.lua b/run.lua index ca1af6d7..fe315e7a 100644 --- a/run.lua +++ b/run.lua @@ -9,6 +9,13 @@ local function quote_if_needed (s) return s end +local function print_exit(msg) + print() + print(string.rep("*",#msg + 4)) + print("* "..msg.." *") + print(string.rep("*",#msg + 4)) +end + -- get the Lua command-line used to invoke this script local cmd = app.lua() @@ -17,7 +24,7 @@ function do_lua_files () print(cmd..' '..f) local res,code = utils.execute(cmd..' '..f) if not res then - print ('process failed with non-zero result: ['..code..'] '..f) + print_exit ('process failed with non-zero result: ['..code..'] '..f) os.exit(1) end end