[Definition]
Mirage: something that appears real or possible but is not in fact so.
Hi Folks,
Recently I used a text editor to open an XML document. Here’s what I saw:
<Document>
<Greeting>Hello, world</Greeting>
</Document>
That is, at the top of the screen I saw:
<Document>
About a centimeter below I saw:
<Greeting>Hello, world</Greeting>
And a centimeter below that I saw:
</Document>
It is a mirage.
There is no vertical dimension in the XML. The XML is just a linear list of symbols:
<Document>NL
<Greeting>Hello, world</Greeting>NL</Document>
The invisible characters I denote by
NL.
The XML consists of the < symbol followed by the D symbol followed by the o symbol followed by …
Another mirage.
There are no <, D, o, … symbols in the XML. The XML is just a series of hex digits:
3C 44 6F 63 75 6D 65 6E 74 3E 0D 0A 20 20 20 20 3C 47 72 65 65 74 69 6E 67 3E 48 65 6C 6C 6F 2C 20 77 6F 72 6C 64 3C 2F 47 72 65 65 74 69 6E 67 3E 0D 0A 3C 2F 44 6F 63 75 6D
65 6E 74 3E
-------------------------------------
The text editor tricks us into thinking that there are 2 dimensions to XML documents and the XML document contains symbols that we recognize as letters of the alphabet, spaces,
punctuation, and other symbols.
The mirage is so good, so compelling that we start to believe that an XML document is essentially a sheet of paper with vertical and horizontal dimensions and with words on
the sheet of paper.
/Roger
P.S. You can replace “XML” with “JSON” or “CSV” or any other text format.
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