A formal grammar for CIF in extended Backus-Naur form.

This is a terse summary of the CIF grammar in an extended Backus-Naur form. An expanded listing with full description is found in the CIF syntax document.

Summary

syntactic unit	syntax	case sensitive?
Basic Structure of a CIF
<CIF>	<Comments>? <WhiteSpace>? { <DataBlock> { <WhiteSpace> <DataBlock> }* { <WhiteSpace> }? }?	yes
<DataBlock>	<DataBlockHeading> {<WhiteSpace> { <DataItems> | <SaveFrame>} }*	yes
<DataBlockHeading>	<DATA_> { <NonBlankChar> }+	no
<SaveFrame>	<SaveFrameHeading> { <WhiteSpace> <DataItems> }+ <WhiteSpace> <SAVE_>	yes
<SaveFrameHeading>	<SAVE_> { <NonBlankChar> }+	no
<DataItems>	<Tag> <WhiteSpace> <Value> | <LoopHeader> <LoopBody>	yes
<LoopHeader>	<LOOP_> {<WhiteSpace> <Tag>}+	no
<LoopBody>	<Value> { <WhiteSpace> <Value> }*	yes
Reserved Words
<DATA_>	{'D' | 'd'} {'A' | 'a'} {'T' | 't'} {'A' | 'a'} '_'	no
<LOOP_>	{'L' | 'l'} {'O' | 'o'} {'O' | 'o'} {'P' | 'p'} '_'	no
<GLOBAL_>	{'G' | 'g'} {'L' | 'l'} {'O' | 'o'} {'B' | 'b'} {'A' | 'a'} {'L' | 'l'} '_'	no
<SAVE_>	{'S' | 's'} {'A' | 'a'} {'V' | 'v'} {'E' | 'e'} '_'	no
<STOP_>	{'S' | 's'} {'T' | 't'} {'O' | 'o'} {'P' | 'p'} '_'	no
Tags and Values
<Tag>	'_'{ <NonBlankChar>}+	no
<Value>	{ '.' | '?' | <Numeric> | <CharString> | <TextField> }	yes
Numeric Values
<Numeric>	{ <Number> | <Number> '(' <UnsignedInteger> ')' }	no
<Number>	{<Integer> | <Float> }	no
<Integer>	{ '+' | '-' }? <UnsignedInteger>	no
<Float>	{ <Integer><Exponent> | { {'+'|'-'} ? { {<Digit>} * '.' <UnsignedInteger> } | { <Digit>} + '.' } } {<Exponent>} ? } }	no
<Exponent>	{ {'e' | 'E' } | {'e' | 'E' } { '+' | '- ' } } <UnsignedInteger>	no
<UnsignedInteger>	{ <Digit> }+	no
<Digit>	{ '0' | '1' | '2' | '3' | '4' | '5' | '6' | '7' | '8' | '9' }	no
Character Strings and Text Fields
<CharString>	<UnquotedString> | <SingleQuotedString> | <DoubleQuotedString>	yes
<eol><UnquotedString>	<eol><OrdinaryChar> {<NonBlankChar>}*	yes
<noteol><UnquotedString>	<noteol>{<OrdinaryChar>|';'} {<NonBlankChar>}*	yes
<SingleQuotedString> <WhiteSpace>	<single_quote>{<AnyPrintChar>}* <single_quote> <WhiteSpace>	yes
<DoubleQuotedString> <WhiteSpace>	<double_quote> {<AnyPrintChar>}* <double_quote> <WhiteSpace>	yes
<TextField>	{ <SemiColonTextField> }	yes
<eol><SemiColonTextField>	<eol>';' { {<AnyPrintChar>}* <eol> {{<TextLeadChar> {<AnyPrintChar>}*}? <eol>}* } ';'	yes
WhiteSpace and Comments
<WhiteSpace>	{ <SP> | <HT> | <eol> | <TokenizedComments>}+	yes
<Comments>	{ '#' {<AnyPrintChar>}* <eol>}+	yes
<TokenizedComments>	{ <SP> | <HT> | <eol> |}+ <Comments>	yes
Character Sets
<OrdinaryChar>	{ '!' | '%' | '&' | '(' | ')' | '*' | '+' | ',' | '-' | '.' | '/' | '0' | '1' | '2' | '3' | '4' | '5' | '6' | '7' | '8' | '9' | ':' | '<' | '=' | '>' | '?' | '@' | 'A' | 'B' | 'C' | 'D' | 'E' | 'F' | 'G' | 'H' | 'I' | 'J' | 'K' | 'L' | 'M' | 'N' | 'O' | 'P' | 'Q' | 'R' | 'S' | 'T' | 'U' | 'V' | 'W' | 'X' | 'Y' | 'Z' | '\' | '^' | '`' | 'a' | 'b' | 'c' | 'd' | 'e' | 'f' | 'g' | 'h' | 'i' | 'j' | 'k' | 'l' | 'm' | 'n' | 'o' | 'p' | 'q' | 'r' | 's' | 't' | 'u' | 'v' | 'w' | 'x' | 'y' | 'z' | '{' | '|' | '}' | '~' }	yes
<NonBlankChar>	<OrdinaryChar> | <double_quote> | '#' | '$' | <single_quote> | '_' |';' | '[' | ']'	yes
<TextLeadChar>	<OrdinaryChar> | <double_quote> | '#' | '$' | <single_quote> | '_' | <SP> | <HT> |'[' | ']'	yes
<AnyPrintChar>	<OrdinaryChar> | <double_quote> | '#' | '$' | <single_quote> | '_' | <SP> | <HT> | ';' | '[' | ']'	yes