[hcoop/debian/mlton.git] / mlyacc / examples / calc / README

This is a sample interactive calculator built using ML-Yacc and ML-Lex.

The calculator is defined by the files

  calc.lex       (* defines lexer *)
  calc.grm       (* defines grammar *)
  calc.sml       (* defines driver function, Calc.parse *)
  calc.mlb       (* ML Basis file *)

To compile this example, type the following commands

  mllex calc.lex
  mlyacc calc.grm
  mlton calc.mlb

in this directory. They will invoke ml-lex and ml-yacc to process the
lexer specification calc.lex and the grammar specification calc.grm
respectively.  Then it will compile the resulting SML source files

  calc.lex.sml
  calc.grm.sig
  calc.grm.sml

and the calc.sml file containing the driver code.

The end result of compiling these files is an executable file named
"calc", that is based on the structure Calc containing a top-level
driver function named parse.

  Calc.parse : unit -> unit

The calculator can be invoked by applying Calc.parse to the unit value.

  - Calc.parse();
  1+3;
  result = 4

The calculator reads a sequence of expressions from the standard input
and prints the value of each expression after reading the expression.
Expressions must be separated by semicolons.  An expression is not
evaluated until the semicolon is encountered.  The calculator
terminates when an end-of-file is encountered. There is no attempt to
fix input errors: a lexical error will cause exception LexError to be
raised, while a syntax error will cause ParseError to be raised.

NOTE: The ML Basis file calc.mlb mentions the ml-yacc library
(ml-yacc-lib.cm). MLton's search path should be configured so that this
library will be found.  This should normally be the case if MLton is
properly installed.
Commit	Line	Data
7f918cf1 CE	1	This is a sample interactive calculator built using ML-Yacc and ML-Lex.
	2
	3	The calculator is defined by the files
	4
	5	calc.lex (* defines lexer *)
	6	calc.grm (* defines grammar *)
	7	calc.sml (* defines driver function, Calc.parse *)
	8	calc.mlb (* ML Basis file *)
	9
	10	To compile this example, type the following commands
	11
	12	mllex calc.lex
	13	mlyacc calc.grm
	14	mlton calc.mlb
	15
	16	in this directory. They will invoke ml-lex and ml-yacc to process the
	17	lexer specification calc.lex and the grammar specification calc.grm
	18	respectively. Then it will compile the resulting SML source files
	19
	20	calc.lex.sml
	21	calc.grm.sig
	22	calc.grm.sml
	23
	24	and the calc.sml file containing the driver code.
	25
	26	The end result of compiling these files is an executable file named
	27	"calc", that is based on the structure Calc containing a top-level
	28	driver function named parse.
	29
	30	Calc.parse : unit -> unit
	31
	32	The calculator can be invoked by applying Calc.parse to the unit value.
	33
	34	- Calc.parse();
	35	1+3;
	36	result = 4
	37
	38	The calculator reads a sequence of expressions from the standard input
	39	and prints the value of each expression after reading the expression.
	40	Expressions must be separated by semicolons. An expression is not
	41	evaluated until the semicolon is encountered. The calculator
	42	terminates when an end-of-file is encountered. There is no attempt to
	43	fix input errors: a lexical error will cause exception LexError to be
	44	raised, while a syntax error will cause ParseError to be raised.
	45
	46	NOTE: The ML Basis file calc.mlb mentions the ml-yacc library
	47	(ml-yacc-lib.cm). MLton's search path should be configured so that this
	48	library will be found. This should normally be the case if MLton is
	49	properly installed.