ndwarshuis
/
org-mode
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

babel-doc: working on Header Arguments -- not quite compiling

This commit is contained in:
Eric Schulte 2010-06-09 16:17:58 -07:00
parent d7b2397184
commit 2760c8e798
1 changed files with 283 additions and 295 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

578
doc/org.texi
View File

@ -10883,6 +10883,7 @@ Using code blocks in table formulas
* Library of Babel::
* Languages::
* Header Arguments::
* Results::
* Noweb Reference Syntax::
* Key Bindings & Useful Functions::
@end menu
@ -11150,11 +11151,11 @@ The original table from reference.org is below; I'm just using the first column
| Haskell | org-babel-doc-haskell | haskell | [[http://www.haskell.org/][haskell]], [[http://projects.haskell.org/haskellmode-emacs/][haskell-mode]], [[http://www.haskell.org/haskellwiki/Haskell_mode_for_Emacs#inf-haskell.el:_the_best_thing_since_the_breadknife][inf-haskell]], [[http://people.cs.uu.nl/andres/lhs2tex/][lhs2tex]] |
| Matlab | [[file:languages/org-babel-doc-octave-matlab.org][org-babel-doc-octave-matlab]] | matlab | matlab, [[http://sourceforge.net/projects/matlab-emacs/][matlab.el]] |
| LaTeX | [[file:languages/org-babel-doc-LaTeX.org][org-babel-doc-latex]] | latex | [[http://www.latex-project.org/][latex]], [[http://www.gnu.org/software/auctex/][auctex]], [[http://www.gnu.org/software/auctex/reftex.html][reftex]] |
| Objective Caml | org-babel-doc-ocaml | ocaml | [[http://caml.inria.fr/][ocaml]], [[http://www-rocq.inria.fr/~acohen/tuareg/][tuareg-mode]] |
| Objective Caml | org-babel-doc-ocaml | ocaml | [[http://caml.inria.fr/][ocaml]], [[http://www-rock.inria.fr/~acohen/tuareg/][tuareg-mode]] |
| Octave | [[file:languages/org-babel-doc-octave-matlab.org][org-babel-doc-octave-matlab]] | octave | octave |
| OZ | [[file:languages/org-babel-doc-oz.org][org-babel-doc-oz]] | oz | [[http://www.mozart-oz.org/][Mozart]] which includes a major mode |
| Perl | org-babel-doc-perl | perl | [[http://www.perl.org/][perl]], [[http://www.emacswiki.org/emacs/CPerlMode][cperl-mode]] (optional) |
| Python | org-babel-doc-python | python | [[http://www.python.org/][python]], [[https://launchpad.net/python-mode][python-mode]] (optional) |
| Python | org-babel-doc-python | python | [[http://www.python.org/][python]], [[https://launch pad.net/python-mode][python-mode]] (optional) |
| R | [[file:languages/org-babel-doc-R.org][org-babel-doc-R]] | R | [[http://www.r-project.org/][R]], [[http://ess.r-project.org/][ess-mode]] |
| Ruby | org-babel-doc-ruby | ruby | [[http://www.ruby-lang.org/][ruby]], [[http://www.ruby-lang.org/][irb]], [[http://github.com/eschulte/rinari/raw/master/util/ruby-mode.el][ruby-mode]], [[http://github.com/eschulte/rinari/raw/master/util/inf-ruby.el][inf-ruby mode]] |
| Sass | org-babel-doc-sass | sass | [[http://sass-lang.com/][sass]], [[http://github.com/nex3/haml/blob/master/extra/sass-mode.el][sass-mode]] |
@ -11175,209 +11176,227 @@ of the language names from the above table).
@end example
@node Header Arguments, Noweb Reference Syntax, Languages, Working With Source Code
@node Header Arguments, Results, Languages, Working With Source Code
@section Header Arguments
:PROPERTIES:
:CUSTOM_ID: header-arguments
:END:
Definitions of all Org-babel header arguments are given
[[header-argument-specific-documentation][below]]. In addition, some
languages may add their own header arguments. Please see the
language-specific documentation for information on language-specific header
arguments.
Definitions of all Org-babel header arguments are given (see @ref{Specific
Header Arguments}). In addition, some languages may add their own header
arguments. Please see the language-specific documentation (available at
@uref{http://orgmode.org/worg/org-contrib/babel/reference.php#languages}.)
for information on language-specific header arguments.
@menu
* Using Header Arguments::
* System-wide Header Arguments::
* Language Specific Header Arguments::
* Header Arguments in Org-mode Properties::
* Header Arguments in Source Code Blocks::
* Specific Header Arguments::
* Using Header Arguments::
@end menu
@node Using Header Arguments, System-wide Header Arguments, , Header Arguments
@subsection Using Header Arguments
The values of header arguments can be set in four different ways, each
more specific (and having higher priority) than the last.
The values of header arguments can be set in four different ways, each more
specific (and having higher priority) than the last.
@subsubsection System-wide
:PROPERTIES:
:CUSTOM_ID: system-wide-header-argument
:END:
@node System-wide Header Arguments, Language Specific Header Arguments, Using Header Arguments, Header Arguments
@subsubsection System-wide Header Arguments
System-wide values of header arguments can be specified by customizing the
@code{org-babel-default-header-args} variable:
System-wide values of header arguments can be specified by
customizing the =org-babel-default-header-args= variable:
@example
org-babel-default-header-args is a variable defined in `org-babel.el'.
Its value is
((:session . "none")
(:results . "replace")
(:exports . "code")
(:cache . "no")
(:noweb . "no"))
@example
org-babel-default-header-args is a variable defined in `org-babel.el'.
Its value is
((:session . "none")
(:results . "replace")
(:exports . "code")
(:cache . "no")
(:noweb . "no"))
Documentation:
Default arguments to use when evaluating a source block.
@end example
[[#default-noweb]]
For example, the following example could be used to set the default value
of =:noweb= header arguments to =yes=. This would have the effect of
expanding =:noweb= references by default when evaluating source code blocks.
@example
(setq org-babel-default-header-args
(cons '(:noweb . "yes")
(assq-delete-all :noweb org-babel-default-header-args)))
@end example
Documentation:
Default arguments to use when evaluating a source block.
@end example
@subsubsection Org-mode Properties
For example, the following example could be used to set the default value of
@code{:noweb} header arguments to =yes=. This would have the effect of
expanding @code{:noweb} references by default when evaluating source code
blocks.
Header arguments are also read from
[[http://orgmode.org/manual/Properties-and-Columns.html#Properties-and-Columns][Org-mode
properties]], which can be set on a buffer-wide or per-heading basis. An
example of setting a header argument for all code blocks in a buffer is
@example
(setq org-babel-default-header-args
(cons '(:noweb . "yes")
(assq-delete-all :noweb org-babel-default-header-args)))
@end example
#+begin_example
@node Language Specific Header Arguments, Header Arguments in Org-mode Properties, System-wide Header Arguments, Header Arguments
@subsubsection Header Arguments in Org-mode Properties
Each language can define it's own set of default header arguments.
@node Header Arguments in Org-mode Properties, Header Arguments in Source Code Blocks, Language Specific Header Arguments, Header Arguments
@subsubsection Header Arguments in Org-mode Properties
Header arguments are also read from Org-mode properties (see @ref{Property
syntax}), which can be set on a buffer-wide or per-heading basis. An example
of setting a header argument for all code blocks in a buffer is
@example
#+property: tangle yes
#+end_example
@end example
When properties are used to set default header arguments, they are looked up
with inheritance, so the value of the =:cache= header argument will default
to true in all source code blocks in the subtree rooted at the following
heading:
@example
* outline header
:PROPERTIES:
:cache: yes
:CUSTOM_ID: property-set-header-arguments
:END:
@end example
Properties defined in this way override the properties set in
=org-babel-default-header-args=. It is convenient to use the
=org-set-property= function bound to =C-c C-x p= to set properties
in Org-mode documents.
@subsubsection Source Code Block
@example
* outline header
:PROPERTIES:
:CUSTOM_ID: single-block-header-arguments
:cache: yes
:CUSTOM_ID: property-set-header-arguments
:END:
The most common way to assign values to header arguments is at the
source code block level. This can be done by listing a sequence of
header arguments and their values as part of the =#+begin_src=
line. Properties set in this way override both the values of
=org-babel-default-header-args= and header argument specified as
properties. In the following example, the
=:results= header argument is set to =silent=, meaning the results
of execution will not be inserted in the buffer, and the =:exports=
header argument is set to =code=, meaning only the body of the
source code block
will be preserved on export to HTML or LaTeX.
@example
#+source: factorial
#+begin_src haskell :results silent :exports code
fac 0 = 1
fac n = n * fac (n-1)
#+end_src
@end example
@end example
Properties defined in this way override the properties set in
@code{org-babel-default-header-args}. It is convenient to use the
@code{org-set-property} function bound to @key{C-c C-x p} to set properties
in Org-mode documents.
@node Header Arguments in Source Code Blocks, Specific Header Arguments, Header Arguments in Org-mode Properties, Header Arguments
@subsubsection Header Arguments in Source Code Block
The most common way to assign values to header arguments is at the source
code block level. This can be done by listing a sequence of header
arguments and their values as part of the @code{#+begin_src} line.
Properties set in this way override both the values of
@code{org-babel-default-header-args} and header argument specified as
properties. In the following example, the @code{:results} header argument
is set to @code{silent}, meaning the results of execution will not be
inserted in the buffer, and the @code{:exports} header argument is set to
@code{code}, meaning only the body of the source code block will be
preserved on export to HTML or LaTeX.
@example
#+source: factorial
#+begin_src haskell :results silent :exports code
fac 0 = 1
fac n = n * fac (n-1)
#+end_src
@end example
@node Specific Header Arguments, , Header Arguments in Source Code Blocks, Header Arguments
@subsection Specific Header Arguments
:PROPERTIES:
:CUSTOM_ID: header-argument-specific-documentation
:END:
Description of every standard (non language-specific) Org-babel header
argument.
@subsubsection =:var=
:PROPERTIES:
:CUSTOM_ID: header-argument-var
:END:
@menu
* @code{var}::
* @code{results}::
* @code{file}::
* @code{dir} and remote execution::
* @code{exports}::
* @code{tangle}::
* @code{session}::
* @code{noweb}::
* @code{cache}::
@end menu
The =:var= header argument is used to pass arguments to
source code blocks. The specifics of how arguments are included
in a source code block are language specific and are
addressed in the language-specific documentation. However, the
syntax used to specify arguments is the same across all
languages. The values passed to arguments can be or
- literal values
- values from org-mode tables
- the results of other source code blocks
@node @code{var}, @code{results}, , Specific Header Arguments
@subsubsection @code{var}
The @code{:var} header argument is used to pass arguments to
source code blocks. The specifics of how arguments are included
in a source code block are language specific and are
addressed in the language-specific documentation. However, the
syntax used to specify arguments is the same across all
languages. The values passed to arguments can be or
- literal values
- values from org-mode tables
- the results of other source code blocks
These values can be indexed in a manner similar to arrays -- see
[[var-argument-indexing][argument indexing]].
These values can be indexed in a manner similar to arrays -- see argument
indexing FIXME/need section on argument indexing.
The following syntax is used to pass arguments to source code
blocks using the =:var= header argument.
The following syntax is used to pass arguments to source code
blocks using the @code{:var} header argument.
@example
:var name=assign
@end example
@example
:var name=assign
@end example
where =assign= can take one of the following forms
where @code{assign} can take one of the following forms
- literal value :: either a string ="string"= or a number =9=.
- reference :: a table name:
- literal value :: either a string @code{"string"} or a number @code{9}.
- reference :: a table name:
@example
#+tblname: example-table
| 1 |
| 2 |
| 3 |
| 4 |
@example
#+tblname: example-table
| 1 |
| 2 |
| 3 |
| 4 |
#+source: table-length
#+begin_src emacs-lisp :var table=example-table
(length table)
#+end_src
#+source: table-length
#+begin_src emacs-lisp :var table=example-table
(length table)
#+end_src
#+results: table-length
: 4
@end example
#+results: table-length
: 4
@end example
a source code block name, as assigned by =#+srcname:=,
followed by parentheses:
a source code block name, as assigned by =#+srcname:=,
followed by parentheses:
@example
#+begin_src emacs-lisp :var length=table-length()
(* 2 length)
#+end_src
@example
#+begin_src emacs-lisp :var length=table-length()
(* 2 length)
#+end_src
#+results:
: 8
@end example
#+results:
: 8
@end example
In addition, an argument can be passed to the source code
block referenced by =:var=. The argument is passed within
the parentheses following the source code block name:
In addition, an argument can be passed to the source code
block referenced by =:var=. The argument is passed within
the parentheses following the source code block name:
@example
#+source: double
#+begin_src emacs-lisp :var input=8
(* 2 input)
#+end_src
@example
#+source: double
#+begin_src emacs-lisp :var input=8
(* 2 input)
#+end_src
#+results: double
: 16
#+results: double
: 16
#+source: squared
#+begin_src emacs-lisp :var input=double(input=1)
(* input input)
#+end_src
#+source: squared
#+begin_src emacs-lisp :var input=double(input=1)
(* input input)
#+end_src
#+results: squared
: 4
@end example
#+results: squared
: 4
@end example
@subsubheading alternate argument syntax
:PROPERTIES:
:CUSTOM_ID: alternate-argument-syntax
:END:
It is also possible to specify arguments in a potentially more
natural way using the =#+source:= line of a source code block.
As in the following example arguments can be packed inside of
parenthesis following the source name.
It is also possible to specify arguments in a potentially more
natural way using the =#+source:= line of a source code block.
As in the following example arguments can be packed inside of
parenthesis following the source name.
@example
#+source: double(input=0)
#+begin_src emacs-lisp
(* 2 input)
#+end_src
@end example
@example
#+source: double(input=0)
#+begin_src emacs-lisp
(* 2 input)
#+end_src
@end example
**** indexable variable values
:PROPERTIES:
:CUSTOM_ID: var-argument-indexing
:END:
It is possible to assign a portion of a value to a
variable in a source block. The following example
@ -11423,10 +11442,8 @@ heading:
function) and =describe-variable= (M-x describe variable)
functions, respectively.
@subsubsection =:results=
:PROPERTIES:
:CUSTOM_ID: header-argument-results
:END:
@node @code{results}, @code{file}, @code{var}, Specific Header Arguments
@subsubsection @code{results}
There are three types of results header argument:
- *collection* header arguments specify how the results should be collected from
@ -11451,13 +11468,13 @@ heading:
of the last statement in the source code block.
This header argument places Org-babel in functional
mode. Note that in some languages, e.g., python,
use of this result type requires that a =return=
use of this result type requires that a @code{return}
statement be included in the body of the source code
block. E.g., =:results value=.
block. E.g., @code{:results value}.
- output :: The result is the collection of everything printed
to stdout during the execution of the source code
block. This header argument places Org-babel in scripting
mode. E.g., =:results output=.
mode. E.g., @code{:results output}.
@subsubheading type
The following options are mutually exclusive and specify what
@ -11467,28 +11484,28 @@ heading:
- table, vector :: The results should be interpreted as an Org-mode table.
If a single value is returned, Org-babel will convert it
into a table with one row and one column. E.g., =:results
value table=.
into a table with one row and one column. E.g., @code{:results
value table}.
- scalar, verbatim :: The results should be interpreted
literally -- meaning they will not be converted into a table.
The results will be inserted into the Org-mode buffer as
quoted text. E.g., =:results value verbatim=.
quoted text. E.g., @code{:results value verbatim}.
- file :: The results will be interpreted as the path to a file,
and will be inserted into the Org-mode buffer as a file
link. E.g., =:results value file=.
link. E.g., @code{:results value file}.
- raw, org :: The results are interpreted as raw Org-mode code and
are inserted directly into the buffer. If the results look
like a table they will be aligned as such by Org-mode.
E.g., =:results value raw=.
E.g., @code{:results value raw}.
- html :: Results are assumed to be HTML and will be enclosed in
a =begin_html= block. E.g., =:results value html=.
a @code{begin_html} block. E.g., @code{:results value html}.
- latex :: Results assumed to be LaTeX and are enclosed in a
=begin_latex= block. E.g., =:results value latex=.
@code{begin_latex} block. E.g., @code{:results value latex}.
- code :: Result are assumed to be parseable code and are
enclosed in a code block. E.g., =:results value code=.
enclosed in a code block. E.g., @code{:results value code}.
- pp :: The result is converted to pretty-printed code and is
enclosed in a code block. This option currently supports
Emacs Lisp, python, and ruby. E.g., =:results value pp=.
Emacs Lisp, python, and ruby. E.g., @code{:results value pp}.
@subsubheading handling
The following results options indicate what Org-babel should do
@ -11496,48 +11513,40 @@ heading:
- silent :: The results will be echoed in the minibuffer but
will not be inserted into the Org-mode buffer. E.g.,
=:results output silent=.
@code{:results output silent}.
- replace :: The default value. The results will be inserted
into the Org-mode buffer. E.g., =:results output
replace=.
into the Org-mode buffer. E.g., @code{:results output
replace}.
@subsubsection =:file=
:PROPERTIES:
:CUSTOM_ID: header-argument-file
:END:
@node @code{file}, @code{dir} and remote execution, @code{results}, Specific Header Arguments
@subsubsection @code{file}
@code{:file} is used to specify a path for file output in which case an
Org-mode style link (see @ref{Link format}) @code{file:} link is inserted
into the buffer as the result. Common examples are graphical output from
R, gnuplot, ditaa and LaTeX blocks.
=:file= is used to specify a path for file output in which case an
[[http://orgmode.org/manual/Link-format.html#Link-format][org style]] =file:= link is inserted into the buffer as the
result. Common examples are graphical output from [[file:languages/org-babel-doc-R.org][R]], gnuplot,
ditaa and [[file:languages/org-babel-doc-LaTeX.org][latex]] blocks.
Note that for some languages, including R, gnuplot, LaTeX and ditaa,
graphical output is sent to the specified file without the file being
referenced explicitly in the code block. See the documentation for the
individual languages for details. In contrast, general purpose languages
such as python and ruby require that the code explicitly create output
corresponding to the path indicated by @code{:file}.
See the [[#header-argument-dir][=:dir= and remote execution]] section for examples.
While the @code{:file} header argument can be used to specify the path to
the output file,
Note that for some languages, including [[file:languages/org-babel-doc-R.org][R]], gnuplot, [[file:languages/org-babel-doc-LaTeX.org][latex]] and
ditaa, graphical output is sent to the specified file without the
file being referenced explicitly in the code block. See the
documentation for the individual languages for details. In
contrast, general purpose languages such as python and ruby
require that the code explicitly create output corresponding to
the path indicated by =:file=.
While the =:file= header argument can be used to specify the path
to the output file,
@subsubsection =:dir= and remote execution
:PROPERTIES:
:CUSTOM_ID: header-argument-dir
:END:
=:dir= specifies the /default directory/ during code block
@node @code{dir} and remote execution, @code{exports}, @code{file}, Specific Header Arguments
@subsubsection @code{dir} and remote execution
@code{:dir} specifies the /default directory/ during code block
execution. If it is absent, then the directory associated with the
current buffer is used. In other words, supplying =:dir path=
temporarily has the same effect as changing the current directory
with =M-x cd path=, and then not supplying =:dir=. Under the
surface, =:dir= simply sets the value of the emacs variable
=default-directory=.
current buffer is used. In other words, supplying @code{:dir path}
temporarily has the same effect as changing the current directory with
@key{M-x cd path}, and then not supplying @code{:dir}. Under the surface,
@code{:dir} simply sets the value of the emacs variable
@code{default-directory}.
When using =:dir=, you should supply a relative path for [[#header-argument-file][file
output]] (e.g. =:file myfile.jpg= or =:file results/myfile.jpg=) in
When using @code{:dir}, you should supply a relative path for file output
(e.g. @code{:file myfile.jpg} or @code{:file results/myfile.jpg}) in
which case that path will be interpreted relative to the default
directory.
@ -11551,9 +11560,9 @@ heading:
@end example
@subsubheading Remote execution
A directory on a remote machine can be specified using [[http://www.gnu.org/software/tramp/#Filename-Syntax][tramp
filename syntax]], in which case the code will be evaluated on the
remote machine[fn:2]. An example is
A directory on a remote machine can be specified using tramp file
syntax, in which case the code will be evaluated on the remote
machine. An example is
@example
#+begin_src R :file plot.png :dir /dand@@yakuba.princeton.edu:
@ -11573,95 +11582,82 @@ and a link of the following form will be inserted in the org buffer:
[[file:/scp:dand@@yakuba.princeton.edu:/home/dand/plot.png][plot.png]]
@end example
Most of this functionality follows immediately from the fact that
=:dir= sets the value of the emacs variable =default-directory=,
thanks to [[http://www.gnu.org/software/tramp/][tramp]]. Those using XEmacs, or GNU Emacs prior to
version 23 may need to install tramp separately in order for the
above features to work correctly.
Most of this functionality follows immediately from the fact that @code{:dir}
sets the value of the emacs variable @code{default-directory}, thanks to
tramp. Those using XEmacs, or GNU Emacs prior to version 23 may need to
install tramp separately in order for the above features to work correctly.
@subsubheading Further points
- If =:dir= is used in conjunction with =:session=, although it
- If @code{:dir} is used in conjunction with @code{:session}, although it
will determine the starting directory for a new session as
expected, no attempt is currently made to alter the directory
associated with an existing session.
- =:dir= should typically not be used to create files during
export with =:exports results= or =:exports both=. The reason
- @code{:dir} should typically not be used to create files during
export with @code{:exports results} or @code{:exports both}. The reason
is that, in order to retain portability of exported material
between machines, during export, links inserted into the buffer
will *not* be expanded against default directory. Therefore, if
default-directory is altered using =:dir=, it it probable that
default-directory is altered using @code{:dir}, it it probable that
the file will be created in a location to which the link does
not point.
@subsubsection =:exports=
:PROPERTIES:
:CUSTOM_ID: header-argument-exports
:END:
@node @code{exports}, @code{tangle}, @code{dir} and remote execution, Specific Header Arguments
@subsubsection @code{exports}
Specify what should be included in HTML or LaTeX exports of the
Org-mode file.
- code :: the default. The body of code is included
into the exported file. E.g., =:exports code=.
into the exported file. E.g., @code{:exports code}.
- results :: the result of evaluating the code is included in the
exported file. E.g., =:exports results=.
exported file. E.g., @code{:exports results}.
- both :: both the code and results are included in the exported
file. E.g., =:exports both=.
file. E.g., @code{:exports both}.
- none :: nothing is included in the exported file. E.g.,
=:exports none=.
@subsubsection =:tangle=
:PROPERTIES:
:CUSTOM_ID: tangle-header-arguments
:END:
@code{:exports none}.
@node @code{tangle}, @code{session}, @code{exports}, Specific Header Arguments
@subsubsection @code{tangle}
Specify whether or not the source code block should be included
in tangled extraction of source code files.
- yes :: the source code block is exported to a source code file
named after the basename (name w/o extension) of the
Org-mode file. E.g., =:tangle yes=.
Org-mode file. E.g., @code{:tangle yes}.
- no :: the default. The source code block is not
exported to a source code file. E.g., =:tangle no=.
- other :: Any other string passed to the =:tangle= header argument
exported to a source code file. E.g., @code{:tangle no}.
- other :: Any other string passed to the @code{:tangle} header argument
is interpreted as a file basename to which the block will
be exported. E.g., =:tangle basename=.
@subsubsection =:session=
:PROPERTIES:
:CUSTOM_ID: header-argument-session
:END:
be exported. E.g., @code{:tangle basename}.
@node @code{session}, @code{noweb}, @code{tangle}, Specific Header Arguments
@subsubsection @code{session}
Start a session for an interpreted language where state is
preserved. This applies particularly to the supported languages
python, R and ruby.
By default, a session is not started.
A string passed to the =:session= header argument will give the
A string passed to the @code{:session} header argument will give the
session a name. This makes it possible to run concurrent
sessions for each interpreted language.
@subsubsection =:noweb=
:PROPERTIES:
:CUSTOM_ID: header-argument-noweb
:END:
@node @code{noweb}, @code{cache}, @code{session}, Specific Header Arguments
@subsubsection @code{noweb}
Controls the expansion of [[noweb-reference-syntax][noweb syntax]] references in a
source code block. This header argument can have one of two
values: =yes= or =no=.
- =no= :: the default. No [[noweb-reference-syntax][noweb syntax]] specific action is taken
values: @code{yes} or @code{no}.
- @code{no} :: the default. No [[noweb-reference-syntax][noweb syntax]] specific action is taken
on evaluating source code blocks/ However, noweb references
will still be expanded during tangling.
- =yes= :: all [[noweb-reference-syntax][noweb syntax]] references in the body of the source
- @code{yes} :: all [[noweb-reference-syntax][noweb syntax]] references in the body of the source
code block will be expanded before the block is evaluated.
@subsubheading Noweb Prefix Lines
Noweb insertions are now placed behind the line prefix of the
=<<reference>>=.
@code{<<reference>>}.
This behavior is illustrated in the following example. Because
the =<<example>>= noweb reference appears behind the SQL
the @code{<<example>>} noweb reference appears behind the SQL
comment syntax, each line of the expanded noweb reference will
be commented.
@ -11685,80 +11681,72 @@ above features to work correctly.
Thanks to Sébastien Vauban for this idea.
@subsubsection =:cache=
:PROPERTIES:
:CUSTOM_ID: header-argument-cache
:END:
@node @code{cache}, , @code{noweb}, Specific Header Arguments
@subsubsection @code{cache}
Controls the use of in-buffer caching of source code block
results to avoid re-running unchanged source code blocks. This
header argument can have one of two values: =yes= or =no=.
- =no= :: The default. No caching takes place and the source
header argument can have one of two values: @code{yes} or @code{no}.
- @code{no} :: The default. No caching takes place and the source
code block will be run every time it is evaluated.
- =yes= :: every time the source code block is run a sha1 hash of
- @code{yes} :: every time the source code block is run a sha1 hash of
the code and arguments passed to the block will be
generated. This hash is packed into the =#+results:= line
generated. This hash is packed into the @code{#+results:} line
of the results and will be checked on subsequent executions
of the source code block. If the source code block has not
changed since the last time it was evaluated, it will not be
re-evaluated.
@node Results, Noweb Reference Syntax, Header Arguments, Working With Source Code
@section Results
:PROPERTIES:
:CUSTOM_ID: results-specification
:END:
The way in which results are handled depends on whether a [[header-argument-session][session]]
is invoked, as well as on whether
[[header-argument-results-collection][=:results value=] or
[[header-argument-results-collection][=:results output=]] is used. The following table shows the
possibilities:
The way in which results are handled depends on whether a
[[header-argument-session][session]] is invoked, as well as on whether
@code{:results value} or @code{:results output} is used. The following
table shows the possibilities:
| | non-session (default) | =:session= |
|-------------------+--------------------------+-------------------------------------|
| =:results value= | value of last expression | value of last expression |
| =:results output= | contents of stdout | concatenation of interpreter output |
*Note:* With =:results value=, the result in both =:session= and
*Note:* With @code{:results value}, the result in both @code{:session} and
non-session is returned to Org-mode as a table (a one- or
two-dimensional vector of strings or numbers) when appropriate.
@subsection Non-session
@subsubsection =:results value=
@subsubsection @code{:results value}
This is the default. Internally, the value is obtained by
wrapping the code in a function definition in the external
language, and evaluating that function. Therefore, code should be
written as if it were the body of such a function. In particular,
note that python does not automatically return a value from a
function unless a =return= statement is present, and so a
function unless a @code{return} statement is present, and so a
'return' statement will usually be required in python.
This is the only one of the four evaluation contexts in which the
code is automatically wrapped in a function definition.
@subsubsection =:results output=
@subsubsection @code{:results output}
The code is passed to the interpreter as an external process, and
the contents of the standard output stream are returned as
text. (In certain languages this also contains the error output
stream; this is an area for future work.)
@subsection =:session=
@subsubsection =:results value=
The code is passed to the interpreter running as an interactive
Emacs inferior process. The result returned is the result of the
last evaluation performed by the interpreter. (This is obtained in
a language-specific manner: the value of the variable =_= in
python and ruby, and the value of =.Last.value= in R).
@subsubsection =:results output=
The code is passed to the interpreter running as an interactive
Emacs inferior process. The result returned is the concatenation
of the sequence of (text) output from the interactive
interpreter. Notice that this is not necessarily the same as what
would be sent to stdout if the same code were passed to a
non-interactive interpreter running as an external process. For
example, compare the following two blocks:
@subsection @code{:session}
@subsubsection @code{:results value}
The code is passed to the interpreter running as an interactive Emacs
inferior process. The result returned is the result of the last
evaluation performed by the interpreter. (This is obtained in a
language-specific manner: the value of the variable @code{_} in python
and ruby, and the value of @code{.Last.value} in R).
@subsubsection @code{:results output}
The code is passed to the interpreter running as an interactive Emacs
inferior process. The result returned is the concatenation of the
sequence of (text) output from the interactive interpreter. Notice
that this is not necessarily the same as what would be sent to
@code{STDOUT} if the same code were passed to a non-interactive
interpreter running as an external process. For example, compare the
following two blocks:
@example
#+begin_src python :results output
@ -11791,7 +11779,7 @@ above features to work correctly.
unnecessary here).
@node Noweb Reference Syntax, Key Bindings & Useful Functions, Header Arguments, Working With Source Code
@node Noweb Reference Syntax, Key Bindings & Useful Functions, Results, Working With Source Code
@section Noweb Reference Syntax
The [[http://www.cs.tufts.edu/~nr/noweb/][Noweb]] Literate Programming system allows named blocks of code to
be referenced by using the familiar Noweb syntax: