Low Level
This web page/document includes miscellaneous low-level details (Alastair, Brian, and Sam can safely ignore it) in regards to JynoLisp implementation, some of which are obsolete.
Public Fields
Public fields are JynoLisp fields (method variables) which are declared in a var block, whereas private (inner) fields are declared in an ivar block. Public fields which include getters and/or setters cannot be modified directly using an assignment statement, except within the class in which they are declared. For a field called myfield, the corresponding getter method is called get-myfield, and the corresponding setter method is called set-myfield. For a boolean field called myfield, the corresponding getter method is called is-myfield. For a boolean field called is-myfield, the corresponding getter method is called get-myfield.
JynoLisp Parsing
Parser uses following sets of initial chars. (in parentheses or on separate line) to help determine class of tokens encountered.
- Alpha:
- keyword ( a-z )
- built-in function ( a-z )
- system function* ( _ )
- Identifiers:
- local variable ( A-Z, _ )
- field ( A-Z, _ )
- method ( A-Z, _ )
- class ( A-Z, _ )
- Numeric:
- 0-9, -
- Punctuation:
- (, ), {, }, #, ", $, ;
- Operators:
- +, -, *, /, %, &, |, ^, ~, =, !, <, >, :, ?
- Invalid:
- Literal Chars. ( \, . )
- Symbols ( [, ], ', `, @, comma )
* System function names begin and end with 2 consecutive underscores. User-defined identifiers begin with optional single underscore followed by a letter, and may contain letters of both cases. The other 3 types of identifiers (keywords, built-in functions, system functions) contain lower case letters only.
Oddball characters:
- ( \ ) backslash found only in string literals
- ( . ) period found only in numeric literals
- ( - ) hyphen found at beginning of numeric literals and 3 operators:
- ( negate, subtract, -= )
- ( } ) close brace in string literal must be escaped
Lexical Scanner (Summary)
Each bottom-level category followed by (n), where n = count, category omitted if zero.
- ALPHA
- KEYWORD
- BLTINFUNC
- SYSFUNC
- IDENTIFIER
- NUMERIC
- BINARY
- OCTAL
- HEXADECIMAL
- DECIMAL
- LONG
- FLOAT
- PUNCT
- OPENPAR
- CLOSEPAR
- SEMICOLON
- CMTLINE
- CMTBLK
- STRLIT
- OPERATOR
- INVALID
- ERRSYM
- ERRESC
- ERRDOT
- Error messages:
- Line no., description
Lexical Scanner (Detail)
LN # TYP VAL CNV
==== === === ===
XXX xxx xxx
0001 [ line buf one ]
KWD str op
FUN str
SYS str
ID str
0002 [ line buf two ]
BIN str dec
OCT str dec
HEX str dec
DEC dec dec
LNG dec dec
FLT str val
0003 [ line buf three ]
PAR (
PAR )
PAR ;
CMT {
CMT }
CMT #
STR str
OP str name
ERR str desc
[ omit blank lines ]
Each 4-digit line no. followed by
contents of line in square brackets,
followed by tokens, one per line.
Global boolean: summary/detail
Code Execution
All JynoLisp source code is in Polish notation, in which operators precede their operands. The following algorithm is used, in which operators are stored in one stack and operands in a separate stack. Executable code consists of tree nodes.
rightp = root
while true do
if rightp = 0 then
op = pop operator
if op = root then
return true
if op = while/for/loopbody then
pop rightp from operator stack
continue
if op = if then
pop rightp from operator stack
pop (
continue
if op = block then
pop (
pop if from operator stack
pop (
pop rightp from operator stack
continue
count = 0
while true do
pop operand
if open parenthesis then break
push operand on operator stack
increment count
if op = call then
rightp = handlecall(count)
continue
if op = constructor then
rightp = handlecons(count)
continue
if op = callback then
rightp = handlecallback(count)
continue
pop operand from operator stack
push operand
repeat count - 1 times
pop operand from operator stack
push operand
rightpop = pop
leftpop = pop
push op(leftpop, rightpop)
// (: obj attridx) => obj...
if count = 1 then
if unary op then
push op(pop)
else
rightpop = pop
leftpop = pop
push op(leftpop, rightpop)
rightp = pop operator
continue
currnode = getnode(rightp)
if open parenthesis then
push on operand stack
push rightp on operator stack
rightp = currnode.downp
else if operand then
push on operand stack
rightp = currnode.rightp
else if operator then
push on operator stack
rightp = currnode.rightp
else if funcbody then
handlebody
rightp = currnode.rightp
else if endfunc then
pop downto begin from operator stack
pop rightp from operator stack
else if while/for then
rightp = currnode.rightp
push rightp, while/for on operator stack
else if do then
flag = pop
if not flag then
pop while, rightp from operator stack
pop rightp from operator stack
pop (
else if continue then
pop downto while from operator stack
pop rightp from operator stack
else if break then
pop downto while from operator stack
pop rightp, rightp from operator stack
pop (
else if breakfor then
pop downto for from operator stack
pop rightp, rightp from operator stack
pop (
pop (
else if contfor then
pop downto loopbody from operator stack
pop rightp from operator stack
else if then then
flag = pop
if flag then
rightp = currnode.rightp
else
pop if from operator stack
pop (
pop rightp from operator stack
else
return false
pop downto x from operator stack:
pop multiple from operator stack
if: pop (
while: pop (
do block while flag:
while true do block if not flag then break
handlecons(count):
pop classref from operator stack
gen objref: root 0/1 = instance/class vars
push objref on operator stack
return handlecall(count)
handlecall(count):
pop objref from operator stack
push objref
pop codept from operator stack
return handlecodept(codept, count)
handlecodept(codept, count):
repeat count - 2 times
pop val from operator stack
push val
push count - 1
return codept
handlecallback(count):
pop callback from operator stack
unpack objref, codept
push objref
return handlecodept(codept, count)
handlebody:
count = pop
root = new node
for i = count - 2 downto 0 do
parm = pop
add parm to 1st half of tree[i]
objref = parm
rightp = currnode.rightp
loccount = currnode value
repeat loccount times
add null node to 2nd half of tree
rightp = currnode.rightp