153 lines
5.9 KiB
Modula-2
153 lines
5.9 KiB
Modula-2
DEFINITION MODULE PascalIO;
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(*
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Module: Pascal-like Input/Output
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Author: Ceriel J.H. Jacobs
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Version: $Header$
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This module provides for I/O that is essentially equivalent to the I/O
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provided by Pascal with "text", or "file of char".
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Output buffers are automatically flushed at program termination.
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The CloseOutput routine is just there for compatibility with earlier
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versions of this module.
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*)
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CONST Eos = 0C; (* End of string character *)
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TYPE Text;
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VAR Input, Output: Text; (* standard input and standard output available
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immediately.
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Standard output is not buffered when
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connected to a terminal.
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*)
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VAR Notext: Text; (* Initialize your Text variables with this *)
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PROCEDURE Reset(VAR InputText: Text; Filename: ARRAY OF CHAR);
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(* When InputText indicates an open textfile, it is first flushed
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and closed. Then, the file indicated by "Filename" is opened for reading.
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If this fails, a runtime error results. Otherwise, InputText is
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associated with the new input file.
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*)
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PROCEDURE Rewrite(VAR OutputText: Text; Filename: ARRAY OF CHAR);
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(* When OutputText indicates an open textfile, it is first flushed
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and closed. Then, the file indicated by "Filename" is opened for writing.
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If this fails, a runtime error results. Otherwise, OutputText is
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associated with the new output file.
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*)
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PROCEDURE CloseOutput();
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(* To be called at the end of the program, to flush all output buffers. *)
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(***************************************************************************
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Input routines;
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All these routines result in a runtime error when not called with either
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"Input", or a "Text" value obtained by Reset.
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Also, the routines that actually advance the "read pointer", result in a
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runtime error when end of file is reached prematurely.
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****************************************************************************)
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PROCEDURE NextChar(InputText: Text): CHAR;
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(* Returns the next character from the InputText, 0C on end of file.
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Does not advance the "read pointer", so behaves much like "input^"
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in Pascal. However, unlike Pascal, if Eoln(InputText) is TRUE, it
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returns the newline character, rather than a space.
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*)
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PROCEDURE Get(InputText: Text);
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(* Advances the "read pointer" by one character. *)
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PROCEDURE Eoln(InputText: Text): BOOLEAN;
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(* Returns TRUE if the next character from the InputText is a linefeed.
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Unlike Pascal however, it does not produce a runtime error when
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called when Eof(InputText) is TRUE.
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*)
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PROCEDURE Eof(InputText: Text): BOOLEAN;
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(* Returns TRUE if the end of the InputText is reached. *)
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PROCEDURE ReadChar(InputText: Text; VAR Char: CHAR);
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(* Read a character from the InputText, and leave the result in "Char".
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Unlike Pascal, if Eoln(InputText) is TRUE, the newline character
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is put in "Char".
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*)
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PROCEDURE ReadLn(InputText: Text);
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(* Skip the rest of the current line from the InputText,
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including the linefeed.
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*)
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PROCEDURE ReadInteger(InputText: Text; VAR Integer: INTEGER);
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(* Skip leading blanks, read an optionally signed integer from the
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InputText, and leave the result in "Integer".
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If no integer is read, or when overflow occurs, a runtime error results.
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Input stops at the character following the integer.
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*)
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PROCEDURE ReadCardinal(InputText: Text; VAR Cardinal: CARDINAL);
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(* Skip leading blanks, read a cardinal from the InputText, and leave the
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result in "Cardinal".
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If no cardinal is read, or when overflow occurs, a runtime error results.
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Input stops at the character following the cardinal.
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*)
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PROCEDURE ReadReal(InputText: Text; VAR Real: REAL);
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(* Skip leading blanks, read a real from the InputText, and leave the
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result in "Real".
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Syntax:
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real --> [(+|-)] digit {digit} [. digit {digit}]
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[ E [(+|-)] digit {digit} ]
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If no real is read, or when overflow/underflow occurs, a runtime error
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results.
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Input stops at the character following the real.
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*)
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(***************************************************************************
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Output routines;
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All these routines result in a runtime error when not called with either
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"Output", or a "Text" value obtained by Rewrite.
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****************************************************************************)
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PROCEDURE WriteChar(OutputText: Text; Char: CHAR);
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(* Writes the character "Char" to the OutputText. *)
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PROCEDURE WriteLn(OutputText: Text);
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(* Writes a linefeed to the OutputText. *)
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PROCEDURE Page(OutputText: Text);
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(* Writes a form-feed to the OutputText *)
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PROCEDURE WriteInteger(OutputText: Text; Integer: INTEGER; Width: CARDINAL);
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(* Write integer "Integer" to the OutputText, using at least "Width" places,
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blank-padding to the left if needed.
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*)
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PROCEDURE WriteCardinal(OutputText: Text; Cardinal, Width: CARDINAL);
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(* Write cardinal "Cardinal" to the OutputText, using at least
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"Width" places, blank-padding to the left if needed.
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*)
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PROCEDURE WriteBoolean(OutputText: Text; Boolean: BOOLEAN; Width: CARDINAL);
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(* Write boolean "Boolean" to the OutputText, using at least "Width" places,
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blank-padding to the left if needed.
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Equivalent to WriteString(OutputText, " TRUE", Width), or
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WriteString(OutputText, "FALSE", Width).
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*)
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PROCEDURE WriteString(OutputText: Text;
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String: ARRAY OF CHAR; Width: CARDINAL);
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(* Write string "String" to the OutputText, using at least "Width" places,
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blank-padding to the left if needed.
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The string is terminated either by the character Eos, or by the upperbound
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of the array "String".
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*)
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PROCEDURE WriteReal(OutputText: Text; Real: REAL; Width, Nfrac: CARDINAL);
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(* Write real "Real" to the OutputText. If "Nfrac" = 0, use scientific
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notation, otherwise use fixed-point notation with "Nfrac" digits behind
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the dot.
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Always use at least "Width" places, blank-padding to the left if needed.
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*)
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END PascalIO.
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