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Module Latex


module Latex: sig .. end
LaTeX output.
type t
LaTeX expressions.

LaTeX Pervasives


type size = [ `Baselineskip of float
       | `Baselinestretch of float
       | `Bp of float
       | `Cc of float
       | `Cm of float
       | `Dd of float
       | `Em of float
       | `Ex of float
       | `Fill
       | `In of float
       | `Linewidth of float
       | `Mm of float
       | `Parindent of float
       | `Parskip of float
       | `Pc of float
       | `Pt of float
       | `Sp of float
       | `Stretch of int
       | `Textheight of float
       | `Textwidth of float
       | `Unitlength of float ]
The type of LaTeX sizes. 
val latex_of_size : size -> t
Low level function to be used to make new bindings.

Document


type documentclass = [ `Article
       | `Beamer
       | `Book
       | `Custom of string
       | `Letter
       | `Report
       | `Slides ] 
type documentoptions = [ `A4paper | `Landscape | `Pt of int | `TwoColumn ] 
val document : ?documentclass:documentclass ->
       ?options:documentoptions list ->
       ?title:t ->
       ?author:t ->
       ?date:t ->
       ?prelude:t -> ?packages:(t * t) list -> t -> t
The ~packages argument takes a list of (name, opt) where name is the name of the package and opt is its option. This is equivalent to using several calls to usepackage in the ~prelude.

Variables



Basic Constructors



Variables are similar to LaTeX counters, except that they are computed when pretty-printing the LaTeX AST.

The two basic operations on variables are get and setf. get outputs an ast depending on the current contents of a variable. setf updates the contents of a variable.

get can also use the contents of a variable at a different position in the document. To use a position, you need to declare one first with position. then you can place that position in you document with place. You must not place a position more than one time. If a position isn't placed, the contents of the variables at that position will be the default one.

The final contents of variables is obtained by a fixpoint computation wich is performed by the printing functions Latex.to_buffer, Latex.to_channel, Latex.to_file, Latex.to_string. That fixpoint may not terminate. In that case, the log will tell you which variable did not converge.

type 'a variable 
val variable : ?eq:('a -> 'a -> bool) ->
       ?name:string -> ?printer:('a -> string) -> 'a -> 'a variable
Declare a new variable. The last argument is the default value of the variable.

eq is the equality function on the type of the variable. Default is =.

name and printer are used to print information when the fixpoint calculation diverged.

val setf : 'a variable -> ('a -> 'a) -> t
Change the value of a variable in the rest of the document.
val setf2 : 'a variable -> 'b variable -> ('a -> 'b -> 'b) -> t
setf var_in var_out f Change the value of the variable var_out in the rest of the document using the contents of var_in.
type position
The type of positions in documents.
val position : ?name:string -> unit -> position
Declare a new position. name is used to print information when the fixpoint computation diverged.
val place : position -> t
Place a position in the document.
val get : ?position:position -> 'a variable -> ('a -> t) -> t
Use the contents of a variable to compute part of the document. If get has no parameter position then the current value of the variable is taken. Otherwise it is the value at position.

Useful Stuff About Variables



All these functions are defined using the above constructors.
val set : 'a variable -> 'a -> t
Change the value of a variable.

set x v: return a node which, when evaluated, changes the contents of variable x to value v.

val final : 'a variable -> ('a -> t) -> t
Like get, but the value of the variable is taken at the end of the document.
val incr_var : int variable -> t
Increment an integer variable.

incr_var x is equivalent to setf x (fun x -> x + 1).

val decr_var : int variable -> t
Decrement an integer variable.

decr_var x is equivalent to setf x (fun x -> x - 1).

val vari : int variable -> t
Print an integer variable.

vari x is equivalent to get x (fun x -> text (string_of_int x)).

val varf : float variable -> t
Print a float variable.

varf x is equivalent to get x (fun x -> text (string_of_float x)).

val varb : bool variable -> t
Print a boolean variable.

varb x is equivalent to get x (fun x -> text (string_of_bool x)).

val vars : string variable -> t
Print a string variable.

vars x is equivalent to get x text.

val vart : t variable -> t
Print a variable containing a LaTeX AST.

vart x is equivalent to get x (fun x -> x).

val finali : int variable -> t
Print the last value of an integer variable.

finali x is equivalent to final x (fun x -> text (string_of_int x)).

val finalf : float variable -> t
Print the last value of a float variable.

finalf x is equivalent to final x (fun x -> text (string_of_float x)).

val finalb : bool variable -> t
Print the last value of a boolean variable.

finalb x is equivalent to final x (fun x -> text (string_of_bool x)).

val finals : string variable -> t
Print the last value of a string variable.

finals x is equivalent to final x text.

val finalt : t variable -> t
Print the last value of a variable containing a LaTeX AST.

finalt x is equivalent to final x (fun x -> x).


References and Labels



Example (using the Melt pre-processor):

let lbl_intro = label ()

let intro = section ~label: lbl_intro "This is Section~{ref_ lbl_intro}."

type label 
val label : ?name:string -> unit -> label
Declare a new label.

Argument name can be used to force the name of the label in the LaTeX file. This can be useful if you need to refer to this label in an external LaTeX file or if the label itself is declared in another LaTeX file. The default value of name is "latex_lib_label_n" where n is a counter.

val ref_ : label -> t
Make a reference to the label.

Figures


type float_position = [ `B | `Force | `H | `P | `T ]
Floating element (figure, ...) positions. 
val float_all : float_position list
[ `H; `T; `B; `P ]
val figure : ?label:label ->
       ?pos:float_position list ->
       ?center:bool ->
       ?side_caption:bool -> ?caption:t -> ?wide:bool -> t -> t
Floating figure.

Default value for center is false. If side_caption is true, the caption will be placed at the side of the figure instead of at the bottom. This uses package sidecap. Default value is false.

Argument ~wide: true must be used for multi-columns documents if you want the figure to use the full width of the page. In this case, positions `H has no effect, and position `B adds package stfloats.

To prevent wide figures from being placed out-of-order with respect to their "non-wide" counterparts, use package fixltx2e.

type wrapfigure_position = [ `Force of [ `I | `L | `O | `R ] | `I | `L | `O | `R ]
Figure positions for package wrapfig. 
val wrapfigure : ?label:label ->
       ?pos:wrapfigure_position ->
       ?lines:int ->
       ?width:size -> ?center:bool -> ?caption:t -> t -> t
Floating figure which makes text wrap around it.

Uses package wrapfig. Argument lines specifies the height of the figure in number of lines. It can be useful if LaTeX fails to compute it correctly. Default value for width is half the text width. Default value for center is false.

If there is too much space on top and below the figure, and lines does not do what you want, you can add some negative vspaces. In general it is better to let LaTeX place the figure for you, though.

type floatingfigure_position = [ `L | `P | `R ]
Figure positions for package floatflt. 
val floatingfigure : ?label:label ->
       ?pos:floatingfigure_position ->
       ?width:size -> ?center:bool -> ?caption:t -> t -> t
Floating figure which makes text wrap around it.

Uses package floatflt. Default value for width is half the text width. Default value for center is false.

val subfloat : ?label:label -> ?caption:t -> t -> t
Sub-figure.

Uses package subfig. Use it inside a figure to insert sub-figures.


Miscellaneous Commands


val hyphen : t
Tell LaTeX where to cut words at the end of lines.
val index : t -> t -> t
index x y produces {x}_{y}
val exponent : t -> t -> t
exponent x y produces {x}^{y}
val index_exponent : t -> t -> t -> t
index_exponent x y z produces {x}_{y}^{z}.

This is NOT equivalent to exponent (index x y) z as this would produce {{x}_{y}}^{z}. The former allows the exponent to be printed above the index, while the latter does not.

val tableofcontents : t
val listoffigures : t
val listoftables : t
val appendix : t
val place_index : t -> t
printindex output an index listing the various point which have been referenced by place_index key. key can be a phrase in which case it appears as-is in the index, or some more complex instruction (documentation for index keys can be found in the Not So Short Introduction to Latex (available online) or the Latex Companion).

If you use at least one of place_index or printindex, a file .idx will be produced at the same time as the .aux. It needs to be processed by the program makeindex (makeindex file.idx). Then (pdf)latex needs to be run again.

val printindex : t
val today : t
val maketitle : t
You should not need maketitle if you use Latex.document.
val part : ?label:label -> t -> t
For the report style.
val chapter : ?label:label -> t -> t
val section : ?label:label -> t -> t
val subsection : ?label:label -> t -> t
val subsubsection : ?label:label -> t -> t
val paragraph : t -> t
val par : t
val displaymath : t -> t
val equation : ?label:label -> t -> t
val hfill : t
val vfill : t
val vfil : t
val footnote : t -> t
val latex_of_int : int -> t
val latex_of_float : float -> t
val itemize : t list -> t
val enumerate : t list -> t
val newline : t
Start a new line.
val newline_size : size -> t
A newline followed by a vertical space.
val newpage : t
Start a new page.
val clearpage : t
Same as newpage, but also force figures and tables floating in the current page to be printed.
val noindent : t
val space : t
Forces a space, same as "\ " in LaTeX
val quad : t
val qquad : t
val includegraphics : t -> t
val symbol : int -> t
val symbolc : char -> t
Convert a char into an int and apply symbol.
val center : t -> t
val flushleft : t -> t
val flushright : t -> t
val minipage : size -> t -> t
val quote : t -> t
val quotation : t -> t
val stackrel : t -> t -> t
val vspace : size -> t
A vertical space.
val hspace : size -> t
An horizontal, possibly negative space.
val addvspace : size -> t
Similar to vspace, but an addvspace x followed by an addvspace y will produce an addvspace of max x y.
val smallskip : t
A small vspace.
val medskip : t
A medium vspace.
val bigskip : t
A big vspace.
val nointerlineskip : t
Delete the interline vertical space.
val phantom : t -> t
Take the space of the argument without actually drawing it
val vphantom : t -> t
Vertical-only phantom
val hphantom : t -> t
Horizontal-only phantom
val parbox : size -> t -> t
A box in which new lines and paragraphs may be used. Useful to display code listings, for instance.
type halignment = [ `C | `L | `R | `S ]
(`C)enter, flush (`L)eft, flush (`R)ight or (`S)pread.
val makebox : size -> ?halign:halignment -> t -> t
A box which only deals with horizontaly aligned material.
val framebox : size -> ?halign:halignment -> t -> t
Same as makebox but draws a frame around the box.
type alignment = [ `C | `L | `R ] 
type array_column = [ `C | `L | `R | `Sep of t | `Vert ] 
type array_line 
val array : array_column list -> array_line list -> t
val array_line : ?sep:size ->
       ?layout:(int * [ `C | `I | `L | `R ]) list ->
       t list -> array_line
Extra alignment `I in layout means that the column inherits the alignment of the first corresponding column in the array layout. The integers in the layout correspond to over how many of the array's column will the cell will span.
val frontmatter : t
val backmatter : t
val mainmatter : t
val underbrace : t -> t -> t
val overbrace : t -> t -> t

Fonts



Font Styles


val emph : t -> t
Emphasize
val texttt : t -> t
Monospace
val textsc : t -> t
Small caps
val textit : t -> t
Italic
val textbf : t -> t
Bold
val textrm : t -> t
Roman
val textsf : t -> t
Sans serif
val mathit : t -> t
Italic (for math mode)
val mathbf : t -> t
Bold (for math mode)
val mathrm : t -> t
Roman (for math mode)
val mathsf : t -> t
Sans serif (for math mode)
val mathcal : t -> t
Caligraphic

Font Sizes



From the smallest to the largest.
val tiny : t -> t
val scriptsize : t -> t
val footnotesize : t -> t
val small : t -> t
val normalsize : t -> t
val large : t -> t
val large2 : t -> t
val large3 : t -> t
val huge : t -> t
val huge2 : t -> t

Math Accents


val hat : t -> t
val grave : t -> t
val bar : t -> t
val acute : t -> t
val mathring : t -> t
val check : t -> t
val dot : t -> t
val vec : t -> t
val breve : t -> t
val tilde : t -> t
val ddot : t -> t
val widehat : t -> t
val widetilde : t -> t

Greek Letters



Lowercase


val alpha : t
val beta : t
val gamma : t
val delta : t
val epsilon : t
val varepsilon : t
val zeta : t
val eta : t
val theta : t
val vartheta : t
val iota : t
val kappa : t
val varkappa : t
val lambda : t
val mu : t
val nu : t
val xi : t
val pi : t
val varpi : t
val rho : t
val varrho : t
val sigma : t
val varsigma : t
val tau : t
val upsilon : t
val phi : t
val varphi : t
val chi : t
val psi : t
val omega : t
val digamma : t

Uppercase


val gamma_ : t
val delta_ : t
val theta_ : t
val lambda_ : t
val xi_ : t
val pi_ : t
val sigma_ : t
val upsilon_ : t
val phi_ : t
val psi_ : t
val omega_ : t

Hebrew Letters


val aleph : t
val beth : t
val gimel : t
val daleth : t

Mathematical Symbols



Binary Relations


val le : t
less or equal
val leq : t
less or equal (same as Latex.le)
val leqslant : t
less or equal (with equal bar parallel to the 'less than' sign
val ge : t
greater or equal
val geq : t
greater or equal (same as Latex.ge)
val geqslant : t
greater or equal (with equal bar parallel to the 'less than' sign
val equiv : t
= with 3 bars
val ll : t
<<
val gg : t
>>
val doteq : t
= with . on top
val prec : t
trumpet <
val succ : t
trumpet >
val sim : t
~
val preceq : t
trumpet < or equal
val succeq : t
trumpet > or equal
val simeq : t
~ or equal
val subset : t
val supset : t
val approx : t
double ~
val subseteq : t
val supseteq : t
val cong : t
= with ~ on top
val sqsubset : t
square strict subset (latexsym package)
val sqsupset : t
square strict superset (latexsym package)
val join_ : t
small bowtie (latexsym package)
val sqsubseteq : t
square subset or equal
val sqsupseteq : t
square superset or equal
val bowtie : t
val in_ : t
in set
val owns : t
inverted in set
val propto : t
infinite with open right buckle
val vdash : t
|-
val dashv : t
-|
val models : t
|=
val mid : t
|
val parallel : t
||
val perp : t
_|_
val smile : t
val frown : t
val asymp : t
frown with smile on top
val not_ : t -> t
generic negation of binary symbol. not_ in_ will print as ∉
val notin : t
not in set (∉)
val ne : t
not equal (≠)
val neq : t
not equal (same as Latex.ne)

Binary Operators


val pm : t
- with + on top (∓)
val mp : t
+ with - on top (±)
val triangleleft : t
◃
val cdot : t
centered .
val div : t
- with . on top and . on the bottom (÷)
val triangleright : t
▹
val times : t
×
val setminus : t
backslash
val star : t
5-branches star
val cup : t
set union
val cap : t
set intersection
val ast : t
asterisk * (6-branches star)
val sqcup : t
square cup
val sqcap : t
square cap
val circ : t
a small circle
val lor_ : t
\/
val land_ : t
/\
val bullet : t
a small filled circle
val oplus : t
a circle with a + inside
val ominus : t
a circle with a - inside
val diamond : t
a small square rotated 45 degrees
val odot : t
a circle with a centered . inside
val oslash : t
a slashed circle
val uplus : t
a cup with a + inside
val otimes : t
a crossed circle
val bigcirc : t
val amalg : t
val bigtriangleup : t
val bigtriangledown : t
val dagger : t
val lhd : t
bigger triangleleft (latexsym package)
val rhd : t
bigger triangleright (latexsym package)
val ddagger : t
double dagger (dagger with one more cross on the bottom)
val unlhd : t
bigger, underlined triangleleft (latexsym package)
val unrhd : t
bigger, underlined triangleright (latexsym package)
val wr : t
a vertical ~

BIG Operators


val sum : t
val prod : t
val coprod : t
val bigcup : t
val bigcap : t
val bigvee : t
val bigwedge : t
val bigsqcup : t
val biguplus : t
val int : t
val oint : t
val bigodot : t
val bigoplus : t
val bigotimes : t

Arrows


val leftarrow : t
<-
val rightarrow : t
->
val to_ : t
-> (same as Latex.rightarrow)
val leftrightarrow : t
<->
val leftarrow_ : t
<=
val rightarrow_ : t
=>
val leftrightarrow_ : t
<=>
val longleftarrow : t
<--
val longrightarrow : t
-->
val longleftrightarrow : t
<-->
val longleftarrow_ : t
<==
val longrightarrow_ : t
==>
val longleftrightarrow_ : t
<==>
val iff : t
<==> (bigger spaces)
val mapsto : t
val longmapsto : t
val hookleftarrow : t
val hookrightarrow : t
val leftharpoonup : t
val rightharpoonup : t
val leftharpoondown : t
val rightharpoondown : t
val rightleftharpoons : t
val uparrow : t
val downarrow : t
val updownarrow : t
val uparrow_ : t
double uparrow
val downarrow_ : t
double downarrow
val updownarrow_ : t
double updownarrow
val nearrow : t
North-East arrow
val searrow : t
South-East arrow
val swarrow : t
South-West arrow
val nwarrow : t
North-West arrow
val leadsto : t
~> (latexsym package)

Symbols to be Sorted (Stay Tuned)


val box_ : t
A square box, for instance to end proofs (QED). Adds package latexsym.
val langle : t
⟨
val rangle : t
⟩
val lceil : t
⌈
val rceil : t
⌉
val frac : t -> t -> t
val land_ : t
/\
val lor_ : t
\/
val lnot : t
¬
val neg : t
¬ (like Latex.lnot)
val forall : t
∀
val exists : t
∃
val top : t
⊤
val bot : t
⊥
val sharp : t
val dots : t
val cdots : t
Centered dots ...
val ldots : t
elipsis, works in math and text mode
val emptyset : t
type doublable_delimiter = [ `Down | `Up | `Up_down | `Vert ] 
type delimiter = [ `Angle
       | `Brace
       | `Bracket
       | `Ceil
       | `Double of doublable_delimiter
       | `Down
       | `Floor
       | `None
       | `Paren
       | `Slash
       | `Up
       | `Up_down
       | `Vert ] 
val left : delimiter -> t
val right : delimiter -> t
val just_left : delimiter -> t -> t
just_left d x: concatenation of left d, x and right `None.
val just_right : delimiter -> t -> t
just_right d x: concatenation of left `None, x and right d.
val between : delimiter -> t -> t
between d x: concatenation of left d, x and right d.
val oe : t
French e in o as in "coeur", "noeud"...

AMS


val mathbb : t -> t
val mathfrak : t -> t
val align : t -> t
the AMS align environment to align equations using &
val align_ : t -> t
same as align, but without numbering
val gather : t -> t
val gather_ : t -> t
val split : t -> t
val proof : ?opt:t -> t -> t
val twoheadrightarrow : t
->>
val square : t
val par_ : t
The paragraph symbol.
val black_triangle_left : t
val black_triangle_right : t

Mathpartir


val mathpar : t list -> t
Math paragraph. This function inserts and commands between each item to split them.
val inferrule : ?lab:t ->
       ?left:t ->
       ?right:t ->
       ?vdots:size ->
       ?width:size ->
       ?leftskip:size ->
       ?rightskip:size -> t list -> t list -> t
Inference rule. inferrule pre post builds an inference rule with pre at the top and post at the bottom. If pre or post is empty, the bar is not drawn.
lab : label to put above the rule
left : label to put on the left of the rule
right : label to put on the right of the rule
vdots : raise the rule and draw vertical dots ; the length argument is translated to a number of line-skips

Saint Mary Road



The package "stmaryrd" is automatically added by these commands.
val llbracket : t
val rrbracket : t

Slide Document Class


val slide : t -> t

Beamer Document Class


module type BEAMER = sig .. end
module Beamer: BEAMER

Verbatim Modes


module Verbatim: sig .. end

Low-Level LaTeX



type mode =
| M
| T
| A
LaTeX mode: math, text or any.

Constructors


val empty : t
The empty LaTeX tree.

Equivalent to concat [] or text "".

val is_empty : t -> bool
Test whether a LaTeX tree is empty.

A concatenation of empty trees is also empty.

A tree containing a Latex.set node is not empty.

A tree containing Latex.get or Latex.final nodes is not empty, even if the call will produce an empty tree when evaluating variables.

val text : string -> t
Raw LaTeX.
val concat : t list -> t
Concatenation.
val (^^) : t -> t -> t
Infix Concatenation.
val command : ?packages:(string * string) list ->
       string ->
       ?opt:mode * t ->
       (mode * t) list -> mode -> t
LaTeX Command.

command name args mode produces the LaTeX command name applied to arguments args.

The command should be used in mode mode. For exemple, the ensuremath LaTeX command should be used in math mode. The command will be coerced using mbox or $ ... $ if mode differs from the mode it is used in.

The opt optional parameter may be used to provide an optional parameter (in brackets []) to the LaTeX command.

Arguments opt and args must be given with their expected mode and will be coerced if needed. For example, the mbox command expect an argument in text mode (the argument must be coerced using $ ... $ if it is math). The ensuremath command expects an argument in any mode.

All packages (name, opt) given using packages will automatically be used by document.

type arg_kind 
val bracket : arg_kind
val brace : arg_kind
val nobr : arg_kind
val unusual_command : ?packages:(string * string) list ->
       string ->
       (mode * arg_kind * t) list -> mode -> t
unusual_command does the same as command, but is more low level. Instead of having a single optional argument and a list of mandatory arguments, it only has a list of arguments.

Each argument comes not only with its content and mode, but with an "argument kind" (type arg_kind) specifying whether it is a brace argument (corresponding to mandatory arguments in command) or a bracket argument (corresponding, in turn, to the option argument of command).

This allows to handle commands which have several optional arguments, or where optional and mandatory arguments are interleaved.

val within_braces : t -> t
within_braces x produces {x}. Typically meant to be used together with unusual_command.
val environment : ?packages:(string * string) list ->
       string ->
       ?opt:mode * t ->
       ?args:(mode * t) list ->
       mode * t -> mode -> t
LaTeX Environment.

Same as function command, except that it only takes one argument (the environment body) and produces an environment, i.e. using the begin and end commands. The args parameters may be used to give additional arguments, such as the columns of an array.

All packages (name, opt) given using packages will automatically be used by document.

val mode : mode -> t -> t
Ensure text or math mode.

mode m x returns x if its mode is already m. If its mode is not m, the result is x coerced using mbox or $ ... $.


Basic blocks to make custom document functions


val documentclass : ?opt:mode * t -> t -> t
All document must start with a single document class declaration, optionnally with arguments. documentclass cls means that cls (represented as a Latex.t) is the class of the document. The optional argument is given as a Latex.t as well, for generality.
val required_packages : t
Your prelude must contain the list of packages required by your document. That is a single occurence of required_packages. Note that it does not make sense out of the document's prelude.
val require_packages : (t * t) list -> t
require_packages takes as argument a list of pairs package,option. Each package is required (see packages) with option option. The argument ~packages of Latex.document is implemented as a require_package. This command can be used anywhere in a document, if needed.
val documentmatter : t -> t
documentmatter body renders your actual document, body, according to the rules specified in the prelude. It is simply LaTeX's document command.

Miscellaneous


val latex : t
"LaTeX" written in a fancy but official way.
val usepackage : ?opt:t -> t -> t
You can use this in the ~prelude of your document, but it is better to use the ~packages argument of document. Note that some commandes add their own packages to the document automatically.
val input : t -> t
Include a LaTeX file. Usually you'd prefer to open an OCaml module, but this can be useful if you have a .tex file with macros that you want to reuse.
val newcommand : int -> t -> t -> t
newcommand parameter_count name body defines a new command with parameter_count arguments, where you can use the ith argument by writing #i in the body, just as in Latex. Normally you'd prefer to just define an OCaml value with let.
val renewcommand : int -> t -> t -> t
Same as newcommand except that it can redefine existing LaTeX commands.
val block : t -> t
block x produces {x}. Should only be used in some rare cases when you want to be very precise about what LaTeX should do. If x is empty, the braces are not added. If you need braces even if x is empty, use Latex.within_braces.
val place_label : label -> t
place_label lbl places label lbl. Normally you would prefer using the various ~label optional arguments available, and only use place_label for unimplemented features or if you are feeling hackish.
val atbegindocument : t -> t
val addcontentsline : t -> t -> t -> t
addcontentsline toc section name
val pagestyle : t -> t
val thispagestyle : t -> t

Printing


type env 
val get_in_env : 'a variable -> env -> 'a

All printing functions take the expected mode as a parameter (default is text). The printed expression will be coerced if its mode differs.
val to_buffer : ?mode:mode -> ?env:env -> Buffer.t -> t -> env
val to_channel : ?mode:mode ->
       ?env:env -> Pervasives.out_channel -> t -> env
val to_file : ?mode:mode -> ?env:env -> string -> t -> env
val to_string : ?mode:mode -> t -> string
val to_string_with_env : ?mode:mode -> ?env:env -> t -> string * env