2. Concrete syntax Quorum A. Stefik (University of Nevada),
S. Siebert (Washington School of Medicine)
integer a variable that holds whole values
if doing something after verifying that something is true
Boolean equals checking whether one thing is the same as another thing
array a variable that references one or more values in a row
class representing something in the computer that exists in the real world
method a list of instructions that represents a tangible behavior
general-purpose language
public a part of a computer program that can be accessed by another program
try attempting to run code that may not run correctly
3. Concrete syntax Quorum
notion non-programmerprogrammer score score
integer numberinteger
number
real
integer
real
8.38
6.20
5.88
6.63
6.46
5.91
float numberdecimal
number
float
decimal
rational
6.81
6.79
6.68
6.70
6.43
6.07
5. Concrete syntax Quorum
assignment x = 1024x = 1024
x is 1024
x =: 1024
x is 1024
x : 1024
7.87
5.77
5.45
6.90
6.32
5.51
type cast use t as Doghandle t as Dog
use t as Dog
cast(t, Dog)
handle t as Dog
apply Dog to t
6.15
5.99
5.85
5.90
5.82
5.46
in Java: (Dog)t
notion non-programmerprogrammer score score
6. Concrete syntax Quorum
increment x = x + 1x = x + 1
x++
x += 1
x + 1
raise x
8.37
7.44
7.14
7.06
5.93
5.49
if statement ifif
when
whenever
when
require
8.37
7.49
6.86
6.89
6.59
6.46
notion non-programmerprogrammer score score
7. Concrete syntax Quorum
notion non-programmerprogrammer
class objectobject structure class structure framework
parent sourcesource parent foundation foundation parentsuper
this selfself me myself myself me
abstract blueprintprototype frame blueprint frame model
return providereturn report provide report return
constant permanentconstant const permanent constant const
try checktest check try test on error
static constantfixed constant static permanent fixed
8. Viscosity of notations
print ”text1” in bold
print ”text2” in bold + italic
print ”text3” in bold + red
print ”text4” in bold
introduce “styles”
style MyStyle is bold
using MyStyle {
print “text1”
print “text2” in italic
print “text3” in red
print “text4”
}
can be easily changed for all usages
modify the style of several items at once
no need to change the style of each individual item repetition viscosity
repetition viscosity
9. Viscosity of notations
knock-on viscosity
repetition viscosity
scope viscosity
violates internal constrains in the programchange in code
their resolution violates further constraints
change in size of input data requires changes to program structure
Turbo Pascal didn’t allow for
dynamic arrays
single action within model requires many repetitive actions
10. Writability and readability
writable syntax
users
not necessarily readable
tool support
readable syntax
can be written effectively
can be read effectively
concise
have to type less
editing support from IDE writability of syntax
code completion
quickfixes
a more concise syntax
tables emphasize readability over writability
11. Writability and readability APL “A Programming Language”
central datatype multidimensional array
to represent most functions and operatorsspecial graphic symbols
very concise code
IBM 2741 special keyboard
12. Writability and readability MUMPS
Massachusetts General
Hospital Utility Multi-
Programming System
no reserved words
abbreviations for concepts
no priority of arithmetic operations
keywords can be used as identifiers
2+3*10 50
14. Learnability and effectiveness
learnable syntax
conceptsthe more
effective syntax
useful for novices
can be “explored” by exploiting IDE support
“press Ctrl+Space
and the tool will
tell you what you
can type next”
have direct meaning in the domain
the easier to learn the language
after learning the language
users can express domain problems effectively
15. Multiple notations
different syntaxes for the same abstract syntax
let users choose
more learnable and verbosebeginners
more effective syntaxexperienced
easy to define several notations
projectional editors
16. IDE supportability SQL
SELECT field1, field2
FROM table1
WHERE ...
FROM table1
SELECT field1, field2
WHERE ...
textual languages syntax can be supported by IDE
code completion
when typing this code,
a user can’t get any support from IDE
because table has not yet been specified
a better syntax
with respect to IDE support
17. IDE supportability functional languages
advantage in terms of IDE support
function call
in either case, function comes first
f(a,b,c)
a.f(b,c)
alternative notation first argument before the dot (optional syntax)
(f a b c)
after the user types “a.”
suggest all functions available for the type of acode completion
much better explorability of the language
