Add 16 operator reference pages and a Relational and Boolean category

docs/commands/device-output/index.adoc

@@ -12,15 +12,21 @@ Commands for device output operations in PostScript.
 
 This category contains PostScript operators for device output.
 
-== Status
+== Commands
 
-This category is ready for command documentation to be added. Commands in this category include operators from the PostScript Language Reference Manual.
+[cols="1,3"]
+|===
+| Command | Description
 
-See other completed categories for documentation examples:
-* link:/commands/references/[Path Construction]
-* link:/commands/references/[Painting]
-* link:/commands/references/[Transformations]
-* link:/commands/references/[Font & Text]
+| link:/commands/references/showpage/[`showpage`]
+| Output the page and reinitialize graphics state (Level 1)
+
+| link:/commands/references/copypage/[`copypage`]
+| Output the page without reinitializing graphics state (Level 1; page retention changes in Level 3)
+
+| link:/commands/references/nulldevice/[`nulldevice`]
+| Discard graphical output (Level 1)
+|===
 
 == See Also
 

docs/commands/font-text/index.adoc

@@ -66,6 +66,9 @@ PostScript provides comprehensive font and text capabilities including font sele
 
 | link:/commands/references/cshow/[`cshow`]
 | Show with per-character control (Level 2)
+
+| link:/commands/references/xyshow/[`xyshow`]
+| Show with explicit x/y displacements (Level 2)
 |===
 
 === Text Measurement

docs/commands/index.adoc

@@ -31,6 +31,10 @@ link:/commands/references/[View all array/string commands →]
 
 link:/commands/references/[View all dictionary commands →]
 
+=== Relational and Boolean
+
+link:/commands/relational-boolean/[View all relational and boolean commands →]
+
 === Control Flow
 
 link:/commands/references/[View all control flow commands →]

docs/commands/references/and.adoc

@@ -0,0 +1,65 @@
+---
+layout: default
+title: and
+parent: Command Reference
+nav_order: 7
+---
+= and
+
+Compute logical or bitwise AND.
+
+== Description
+
+With two booleans, `and` returns true only when both operands are true. With two integers, it applies bitwise AND to their binary representations and returns an integer.
+
+Both operands must have the same type: boolean or integer. Reals and mixed boolean/integer operands cause `typecheck`. This consumes two already evaluated operands; it does not short-circuit execution.
+
+== Syntax
+
+[source,postscript]
+----
+bool1 bool2 and bool3
+int1 int2 and int3
+----
+
+=== Stack Effect
+
+Stack entries are shown from bottom to top; earlier operands are unchanged.
+
+[cols="1,3"]
+|===
+|State |Operand stack
+
+|Before
+|`bool1 bool2` or `int1 int2`
+
+|After
+|`bool3` or `int3`
+|===
+
+== Examples
+
+[source,postscript]
+----
+true false and % false
+true true and  % true
+12 10 and      % 8 (1100 AND 1010 = 1000)
+----
+
+== Related Commands
+
+* link:/commands/references/or/[`or`] - Logical and bitwise operation
+* link:/commands/references/xor/[`xor`] - Logical and bitwise operation
+* link:/commands/references/not/[`not`] - Logical and bitwise operation
+
+== PostScript Level
+
+*Available in*: PostScript Level 1 and higher (LanguageLevel 1).
+
+== Error Conditions
+
+`stackunderflow`::
+The operand stack contains fewer than two operands.
+
+`typecheck`::
+Operands are neither two booleans nor two integers.

docs/commands/references/copypage.adoc

@@ -0,0 +1,64 @@
+---
+layout: default
+title: copypage
+parent: Command Reference
+nav_order: 2
+---
+= copypage
+
+Output the current page without reinitializing the graphics state.
+
+== Description
+
+In Levels 1 and 2, `copypage` outputs the current page while retaining its marks and graphics state, so further drawing can be added to the same image.
+
+In Level 3, it behaves like `showpage` except that it does not reinitialize the graphics state: under normal page-device behavior, the page is output and erased. Do not rely on earlier marks remaining when running in Level 3. Page-device procedures can customize output behavior.
+
+== Syntax
+
+[source,postscript]
+----
+- copypage -
+----
+
+=== Stack Effect
+
+Stack entries are shown from bottom to top; earlier operands are unchanged.
+
+[cols="1,3"]
+|===
+|State |Operand stack
+
+|Before
+|No operands required
+
+|After
+|Unchanged
+|===
+
+== Examples
+
+[source,postscript]
+----
+/Helvetica findfont 12 scalefont setfont
+72 720 moveto (Original) show
+copypage
+72 700 moveto (Additional line) show
+showpage
+% Levels 1/2: the second output contains both lines.
+% Level 3: the second output contains only the additional line.
+----
+
+== Related Commands
+
+* link:/commands/references/showpage/[`showpage`] - Output and reinitialize the graphics state
+* link:/commands/references/nulldevice/[`nulldevice`] - Discard graphical output
+
+== PostScript Level
+
+*Available in*: PostScript Level 1 and higher (LanguageLevel 1).
+
+== Error Conditions
+
+`undefined`::
+In Level 2 and higher, copypage was called from a BeginPage or EndPage procedure. Errors from page-device procedures can also propagate.

docs/commands/references/eq.adoc

@@ -0,0 +1,69 @@
+---
+layout: default
+title: eq
+parent: Command Reference
+nav_order: 1
+---
+= eq
+
+Test two objects for equality.
+
+== Description
+
+Returns `true` when the two operands are equal, and `false` otherwise.
+
+Integers and reals compare by numeric value. Strings compare by their bytes, and names compare by their spelling; a name and a string with the same characters are equal. Other differing types are unequal, rather than causing `typecheck`.
+
+Arrays and dictionaries compare by shared object identity, not by matching contents. Literal/executable attributes do not affect equality. String contents must be readable.
+
+== Syntax
+
+[source,postscript]
+----
+any1 any2 eq bool
+----
+
+=== Stack Effect
+
+Stack entries are shown from bottom to top; earlier operands are unchanged.
+
+[cols="1,3"]
+|===
+|State |Operand stack
+
+|Before
+|`any1 any2`
+
+|After
+|`bool`
+|===
+
+== Examples
+
+[source,postscript]
+----
+7 7.0 eq  % true
+(cat) (cat) eq  % true
+/cat /cat eq  % true
+/cat (cat) eq  % true
+7 (7) eq  % false
+[1 2] dup eq  % true
+[1 2] [1 2] eq  % false
+----
+
+== Related Commands
+
+* link:/commands/references/ne/[`ne`] - Complementary equality test
+* link:/commands/references/lt/[`lt`] - Ordered comparison
+
+== PostScript Level
+
+*Available in*: PostScript Level 1 and higher (LanguageLevel 1).
+
+== Error Conditions
+
+`invalidaccess`::
+A string needed for comparison does not permit reading.
+
+`stackunderflow`::
+The operand stack contains fewer than two operands.

docs/commands/references/false.adoc

@@ -0,0 +1,61 @@
+---
+layout: default
+title: "false"
+parent: Command Reference
+nav_order: 12
+---
+= false
+
+Push the boolean value `false`.
+
+== Description
+
+Executing the name `false` pushes the boolean value `false` onto the operand stack. It takes no operands. Strictly speaking, this is a name in `systemdict` associated with a boolean object, rather than an operator.
+
+Booleans are distinct from integers: `true` is not the number 1, and `false` is not the number 0. Use booleans as conditions for `if` and `ifelse`.
+
+== Syntax
+
+[source,postscript]
+----
+- false false
+----
+
+=== Stack Effect
+
+Stack entries are shown from bottom to top; earlier operands are unchanged.
+
+[cols="1,3"]
+|===
+|State |Operand stack
+
+|Before
+|No operands required
+
+|After
+|`false`
+|===
+
+== Examples
+
+[source,postscript]
+----
+false type     % booleantype
+false not      % true
+false { (yes) } { (no) } ifelse % (no)
+----
+
+== Related Commands
+
+* link:/commands/references/true/[`true`] - The other boolean value
+* link:/commands/references/not/[`not`] - Negate a boolean
+* link:/commands/references/ifelse/[`ifelse`] - Select a branch
+
+== PostScript Level
+
+*Available in*: PostScript Level 1 and higher (LanguageLevel 1).
+
+== Error Conditions
+
+`stackoverflow`::
+The operand stack has no room for another object.

docs/commands/references/ge.adoc

@@ -0,0 +1,70 @@
+---
+layout: default
+title: ge
+parent: Command Reference
+nav_order: 3
+---
+= ge
+
+Test whether the first operand is greater than or equal to the second.
+
+== Description
+
+Returns a boolean indicating whether the first operand is greater than or equal to the second. Both operands must be numbers or both must be strings. Integers and reals may be mixed.
+
+Strings are ordered lexicographically by unsigned byte values, with the first differing byte deciding the order. If one string is a prefix of the other, the shorter string comes first. This is case-sensitive byte ordering, not locale-aware sorting. Names are not accepted, even though names can be compared with strings by `eq` and `ne`.
+
+== Syntax
+
+[source,postscript]
+----
+num1 num2 ge bool
+string1 string2 ge bool
+----
+
+=== Stack Effect
+
+Stack entries are shown from bottom to top; earlier operands are unchanged.
+
+[cols="1,3"]
+|===
+|State |Operand stack
+
+|Before
+|`num1 num2` or `string1 string2`
+
+|After
+|`bool`
+|===
+
+== Examples
+
+[source,postscript]
+----
+5 5.0 ge       % true
+(cat) (car) ge % true
+2 3 ge         % false
+----
+
+== Related Commands
+
+* link:/commands/references/eq/[`eq`] - Compare values
+* link:/commands/references/ne/[`ne`] - Compare values
+* link:/commands/references/gt/[`gt`] - Compare values
+* link:/commands/references/le/[`le`] - Compare values
+* link:/commands/references/lt/[`lt`] - Compare values
+
+== PostScript Level
+
+*Available in*: PostScript Level 1 and higher (LanguageLevel 1).
+
+== Error Conditions
+
+`invalidaccess`::
+A string needed for comparison does not permit reading.
+
+`stackunderflow`::
+The operand stack contains fewer than two operands.
+
+`typecheck`::
+Operands are neither two numbers nor two strings.