(dc.info.gz) Strings

Info Catalog

(dc.info.gz) Parameters

(dc.info.gz) Top

(dc.info.gz) Status Inquiry

 
 Strings
 *******
 
    DC can operate on strings as well as on numbers.  The only things
 you can do with strings are print them and execute them as macros
 (which means that the contents of the string are processed as DC
 commands).  Both registers and the stack can hold strings, and DC
 always knows whether any given object is a string or a number.  Some
 commands such as arithmetic operations demand numbers as arguments and
 print errors if given strings.  Other commands can accept either a
 number or a string; for example, the `p' command can accept either and
 prints the object according to its type.
 
 `[CHARACTERS]'
      Makes a string containing CHARACTERS and pushes it on the stack.
      For example, `[foo]P' prints the characters `foo' (with no
      newline).
 
 `a'
      The mnemonic for this is somewhat erroneous: asciify.  The
      top-of-stack is popped.  If it was a number, then the low-order
      byte of this number is converted into a string and pushed onto the
      stack.  Otherwise the top-of-stack was a string, and the first
      character of that string is pushed back.  (This command is a GNU
      extension.)
 
 `x'
      Pops a value off the stack and executes it as a macro.  Normally
      it should be a string; if it is a number, it is simply pushed back
      onto the stack.  For example, `[1p]x' executes the macro `1p',
      which pushes 1 on the stack and prints `1' on a separate line.
 
      Macros are most often stored in registers; `[1p]sa' stores a macro
      to print `1' into register `a', and `lax' invokes the macro.
 
 `>R'
      Pops two values off the stack and compares them assuming they are
      numbers, executing the contents of register R as a macro if the
      original top-of-stack is greater.  Thus, `1 2>a' will invoke
      register `a''s contents and `2 1>a' will not.
 
 `!>R'
      Similar but invokes the macro if the original top-of-stack is not
      greater (is less than or equal to) what was the second-to-top.
 
 `<R'
      Similar but invokes the macro if the original top-of-stack is less.
 
 `!<R'
      Similar but invokes the macro if the original top-of-stack is not
      less (is greater than or equal to) what was the second-to-top.
 
 `=R'
      Similar but invokes the macro if the two numbers popped are equal.
 
 `!=R'
      Similar but invokes the macro if the two numbers popped are not
      equal.
 
 `?'
      Reads a line from the terminal and executes it.  This command
      allows a macro to request input from the user.
 
 `q'
      During the execution of a macro, this command exits from the macro
      and also from the macro which invoked it.  If called from the top
      level, or from a macro which was called directly from the top
      level, the `q' command will cause DC to exit.
 
 `Q'
      Pops a value off the stack and uses it as a count of levels of
      macro execution to be exited.  Thus, `3Q' exits three levels.
 

Info Catalog

(dc.info.gz) Parameters

(dc.info.gz) Top

(dc.info.gz) Status Inquiry