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One syntax to rule them all

Last modified on 2007/08/11


Design Patterns

The Harpoon language is only a tool and as such can be used properly or not. This section describes how to design data structures correctly in typical situations.

List of Sections Design Pattern

When you need a collection of named entities, first solution that comes to mind is to use record. This however can be an improper decision. Records should be used only to group values describing a single entity, such as a book or other stuff that would typically be contained in one row of a table in relational model.

A different solution should be used for applications similar to the one known from the windows .ini files, where descriptions are organized in sections - i.e. when there is an open set of named entities, each of which could be used separately. In such situations, in Harpoon, one should use a list of tagged descriptions:

Name = English

[Ocr Setting]
Resolution = 0
Document Size = 2

[Scan Setting]
Scan Mode = 1
Resolution = 0
Path = C:\windows\twain_32

Scanner {


name = "English"



resolution = 0

document_size = 2



scan_mode = 1

resolution = 0

path = "C:\\windows\\twain_32"



Header-Body Design Pattern

In programming languages there are many constructs consisting from a header and a body - for example conditional loops and definitions of functions and classes. This schema can be mirrored in Harpoon by using a pair connected with a colon:

while ( k != 0 )

while ( k != 0 ):




if ( is_lowercase(s) ) printf(s);

if is_lowercase(s) : printf(s)


Assuming the construct is contained in a list, the joining colon could actually be removed, although it would split the construct into two separate entities, which would have to be interpreted as a single one on some higher level.