45 lines
3 KiB
Text
45 lines
3 KiB
Text
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# literal strings are called string denotations in Algol 68 #
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# string denotations start and end with a double quote character #
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# there can be 0 or more characters between the quotes #
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# within the quotes, any characters allowed by the implementation can appear #
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# If an embedded double quote is required, it should appear as two double quotes #
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# e.g.: #
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print( ( "String with an embedded "" character", newline ) );
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# string denotations can appear anywhere an "expression" would be allowed, e.g.: #
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STRING x := "some text"; # string denotation used as an initial value #
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print( ( "quoted string", newline ) ); # string denotation used in a procedure call #
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print( ( "[[" + x + "]]", newline ) ); # string denotations used in an expression #
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# note that technically, a single character within double quotes is a character denotation #
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# (character literal) not a string denotation, normally a character denotation will be #
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# automatically coerced to a string denotation if necessary. however it does mean that #
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# custom operators that have string parameters would also need to be defined for #
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# character parameters #
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# e.g.: #
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OP LENGTH = ( STRING a )INT: ( UPB a - LWB a ) + 1; # returns the length of a #
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# in order to make the following print "work", we need to also define : #
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OP LENGTH = ( CHAR a )INT: 1; # returns the length of a, which is always 1 #
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# ---- these are string denotations ------- #
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# vv vvvv vvvvv #
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print( ( LENGTH "", LENGTH "A", LENGTH "AB", LENGTH "BBC", newline ) );
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# ^^^ #
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# this is a character denotation #
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# C-style escapes e.g.: \n, \", \123 are not supported #
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# ALGOL 68RS and algol68toc support "radix strings" where a string-denotation can be #
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# specified as e.g., hexadecimal codes: #
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# 16r" 0D 0A" is carriage-return line-feed #
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# ALGOL 68 Genie allows string denotation to be continued across several lines #
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# if the lines end with \, the \ characters are not part of the string #
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# NB - this is not a standard feature of Algol 68 #
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print( ( "Hello\
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, \
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World\
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!" ) );
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# Algol 68 does not have string-interpolation #
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SKIP
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