Table of Contents

• 1. cvs
  • 1.1. Syntax
  • 1.2. Stack Effects
  • 1.3. Description
  • 1.4. PostScript Level
  • 1.5. Examples
  • 1.6. Common Use Cases
    • 1.6.1. Number to String Conversion
    • 1.6.2. Building Messages
    • 1.6.3. Debug Output
  • 1.7. Common Pitfalls
  • 1.8. Error Conditions
  • 1.9. Implementation Notes
  • 1.10. Recommended Buffer Sizes
  • 1.11. See Also

1. cvs

Converts any object to its string representation.

1.1. Syntax

any string cvs → substring

1.2. Stack Effects

Table 1. Before

Level	Object
1	any (object to convert)
0	string (buffer for result)

Table 2. After

Level	Object
0	substring (portion of string used)

1.3. Description

cvs (convert to string) produces a text representation of an arbitrary object and stores it into the supplied string, overwriting an initial portion of its value. It returns a string object designating the substring actually used.

Conversion rules: * Numbers: Text representation (e.g., 123, 3.14) * Booleans: true or false * Strings: Contents copied verbatim * Names/operators: Text representation of name * Other types: --nostringval--

For real numbers, the exact format is implementation-dependent (e.g., 0.001 or 1.0E-3).

1.4. PostScript Level

Level 1 and later

1.5. Examples

Converting numbers

/str 20 string def
123 456 add str cvs
% Result: (579)

Converting booleans

/str 10 string def
true str cvs     % Result: (true)
false str cvs    % Result: (false)

Converting names

/str 20 string def
/MyName str cvs  % Result: (MyName)

Unconvertible types

/str 20 string def
mark str cvs     % Result: (--nostringval--)

1.6. Common Use Cases

1.6.1. Number to String Conversion

/num 42 def
20 string
num exch cvs
% Use string representation

1.6.2. Building Messages

/message 100 string def
(Value: ) message 0 7 getinterval cvs
value message 8 message length 8 sub getinterval cvs

1.6.3. Debug Output

/debug {
  20 string cvs print (\n) print
} def

123 debug        % Prints "123"
/name debug      % Prints "name"

1.7. Common Pitfalls

Buffer Must Be Large Enough - If string is too small, [rangecheck] error occurs.

123456 3 string cvs  % Error: need at least 6 chars

Real Number Format Varies - Format for reals is implementation-dependent.

0.001 20 string cvs  % Might be (0.001) or (1.0E-3)

Returns Substring - Result is a substring sharing the buffer, not a new string.

/buf 20 string def
123 buf cvs /s1 exch def
456 buf cvs /s2 exch def
% s1 now shows (456...) - buffer was reused!

Use Ample Buffer Size - Allocate at least 20-30 characters for number conversions.

1.8. Error Conditions

Error	Condition
[invalidaccess]	String has no-access or read-only attribute
[rangecheck]	String too small for conversion result
[stackunderflow]	Fewer than 2 operands on stack
[typecheck]	Second operand is not a string

1.9. Implementation Notes

• Numbers converted using PostScript syntax rules

• String result shares the buffer (not a copy)

• For strings, performs a copy operation

• Return value points to used portion of buffer only

1.10. Recommended Buffer Sizes

Object Type	Min Size	Reason
Integers	12	Max ~10 digits plus sign
Reals	30	Scientific notation possible
Names	Variable	Length of name + 1
Booleans	6	"true" or "false"

1.11. See Also

• cvn - Convert string to name

• cvi - Convert to integer

• cvr - Convert to real

• string - Create string buffer

• type - Get object type