fmtlex/src/Scan.i3


Copyright (C) 1994, Digital Equipment Corp.
The Scan interface provides procedures for reading strings, booleans, integers, and floating-point numbers from a text string. Similar functionality on readers is availble from the Lex interface.

INTERFACE Scan;

IMPORT Word, Lex, FloatMode;
Each of these procedures parses a string of characters and converts it to a binary value. Leading and trailing blanks (ie. characters in Lex.Blanks) are ignored. Lex.Error is raised if the first non-blank substring is not generated by the corresponding Lex grammar or if there are zero or more than one non-blank substrings. FloatMode.Trap is raised as per Lex.

PROCEDURE Bool(txt: TEXT): BOOLEAN
  RAISES {Lex.Error};

PROCEDURE Int(txt: TEXT; defaultBase: [2..16] := 10): INTEGER
  RAISES {Lex.Error, FloatMode.Trap};
PROCEDURE Unsigned(txt: TEXT; defaultBase: [2..16] := 16): Word.T
  RAISES {Lex.Error, FloatMode.Trap};

PROCEDURE Real(txt: TEXT): REAL
  RAISES {Lex.Error, FloatMode.Trap};
PROCEDURE LongReal(txt: TEXT): LONGREAL
  RAISES {Lex.Error, FloatMode.Trap};
PROCEDURE Extended(txt: TEXT): EXTENDED
  RAISES {Lex.Error, FloatMode.Trap};

END Scan.

interface FloatMode is in: