Macal DSL is used for collecting and transforming data from various sources.
Project description
Macal DSL 5.5 Alpha 5
Introduction
This is version 5.5 of the Macal DSL language This is an interim version.
I have removed the bytecode compiler and runtime. Version 5.5 is to fix several problems in regards to scope and the way functions were implemented. Version 6.0 will use llvmlite and jit compilation.
Known issues: 1). If you include a file for which there are multiple files in the file search path that have the same file name, there is no way of telling which one gets included. A safeguard is in place to prevent importing a file from itself, but i can't exclude multiple files with the same name on the search path other than the user controlling the search path.
2). The utilities mi and mr have been replaced with mrepl and mrun respectively. Utilities mc and md have been removed.
Installation
python3 -m pip install macal==5.5.0.alpha.5
Usage
Macal can be used in 3 main ways:
1). Use it on the commandline with 'mrepl' to run interactively.
2). Use it on the commandline with 'mrun' to run a file. (type mrun -h to get help).
3). Include the class in your product and work from there. An example will be provided in a later chapter.
4). After installing the mide package you can use the mide utility which is a very simple cli/text based editor/ide.
Instruction set "EBNF"
letter = "a".."z" | "A".."Z"
digit = "0".."9"
ident = letter | "_" | digit
stmt = return_stmt | continue_stmt | break_stmt | halt_stmt | if_stmt | while_stmt | foreach_stmt | switch_stmt | include_stmt | select_stmt | functiondefinition_stmt | external_stmt | vardeclaration_stmt | functioncall_stmt | builtin_functions
builtin_functions = print_stmt | is_type_stmt | type_stmt is_type_stmt = isrecord_stmt | isarray_stmt | isstring_stmt | isint_stmt | isfloat_stmt | isbool_stmt | isnil_stmt | isfunction_stmt | isobject_stmt
return_stmt = "return" [ expr ] ";"
continue_stmt = "continue" ";"
break_stmt = "break" ";"
halt_stmt = "halt" [ expr ] ";"
if_stmt = "if" expr "{" stmt... "}" [ "elif" expr "{" stmt... "}" ... ] [ "else" "{" stmt... "}" ]
while_stmt = "while" expr "{" stmt... "}"
foreach_stmt = "foreach" expr "{" stmt... "}"
switch_stmt = "switch" expr "{" case_stmt... [ default_stmt ] "}"
case_stmt = "case" expr ":" "{" stmt... "}"
default_stmt = "default" ":" "{" stmt... "}"
include_stmt = "include" lib_name [ "," lib_name... ] ";"
select_stmt = "select" [ "distinct" ] field_list "from" expr [ "where" expr ] [ "merge" ] "into" expr ";"
lib_name = ident
field_list = field ([ "," field ])*
field = field_name [ "as" alias ]
field_name = ident
functioncall_stmt = ident "(" expr ["," expr]... ")" ";"
functiondefinition_stmt = ident "=>" "(" [ ident [ "," ident ]... ] ")" "{" stmt... "}"
external_stmt = ident "=>" "(" [ ident [ "," ident ]... ] ")" "external" python_module "," external_function_name
python_module = string_literal
external_function_name = string_literal
vardeclaration_stmt = ident "=" ([ident "="])* expr ";"
isrecord_stmt = isRecord( expr ) ";"
isarray_stmt = isArray( expr ) ";"
isstring_stmt = isString( expr ) ";"
isint_stmt = isInt( expr ) ";"
isfloat_stmt = isFloat( expr ) ";"
isbool_stmt = isBool( expr ) ";"
isnil_stmt = isNil( expr ) ";"
isfunction_stmt = isFunction( expr ) ";"
isobject_stmt = isObject( expr ) ";" ;
type_stmt = "type" "(" expr ")" ";"
print_stmt = "print" "(" expr ([, expr])* ")" ";"
array_variable = ident "[" expression "]"
record_variable = ident ({ "." ident | "[" string_literal "]" })*
string_literal = '"' literal '"'
expr = assignment_expr
assignment_expr = string_concatenation ( "=" | "+=" | "-=" | "*=" | "/=" | "%=" | "^=" | ".=" ) assignment_expr
string_concatenation = object_expr ( "+." ) object_expr
object_expr = object "{" ident ":" expr ([ "," ident ":" expr ])* "}" | array_expr
array_expr = "[" expr (["," expr])* "]"
record_expr = "{" expr (["," expr])* "}"
logical_expr = comparison_expr ("and", "or", "xor", "&&", "||") comparison_expr
comparison_expr = addition_expr ({"<", "<=", ">", ">=", "==", "!="}) addition_expr
addition_expr = multiplication_expr ("+", "-") multiplication_expr
multiplication_expr = power_expr ("*", "/", "%") power_expr
power_expr = unary_expr ("^") unary_expr
unary_expr = ("-", "++", "--") unary_expr | call_member_expr
call_member_expr = member_expr | "(" call_expr
call_expr = args "(" call_expr(callee)
args = "(" arg_list ")"
arg_list = expr (",") expr
member_expr = primary_expr ("." primary_expr | "[" "]" new array_element | "[" expr "]")
new_array_element = "=" expr
primary_expr = ident | int_number | float_number | string_literal | "(" expr ")" | array_literal | record_literal | type_stmt | is_type_stmt
Statements
a = 1; // integer type is inferred from the assignment f = 1.0; // a float b = true; // boolean s = "this is a string"; // string s2 = 'this is also a string'; s3 = $"this is a string with {a} {b} {s} interpolation.";
arr = ["item1", "item2", "item3"]; // create a variable arr that has an array with 3 elements. rec = {"key1": "value1", "key2": 2, "key3": nil}; // create a variable rec with 3 key/value pairs. // alternative method to define the same array and record in a different way. arr = array; arr[] = "item1"; arr[] = "item2"; arr[] = "item3"; rec = record; rec["key1"] = "value1"; rec["key2"] = 2; rec["key3"] = nil;
// getting the value from an array: print(arr[0]); print(arr[2]);
// getting the values from a record, method 1: print(rec["key1"]); print(rec["key2"]); // Alternative way for getting the values from a record: print(rec.key1); print(rec.key2);
print(a); print(s3); print(a, f, b);
if {
} elif {
} else {
}
while { // can use continue to continue the loop. // can use break to break out of the loop. }
foreach { print(it); // The it variable contains the current value of the iterator that is iterating over the iterable. // can use continue to continue the loop. // can use break to break out of the loop. }
func_name => (a, b) { // function definition print(a); print(b); return a + b; }
// Defines a function that links to an external function that lives in a python module // called <module_name>.py with the name <ext_unc_name> func_name_2 => (a, b) external "<module_name>", "<ext_func_name>";
switch { case : { break; } case : {
}
case <expr>: {
}
default : {
}
}
q = [{}]; select distinct a as b from x() where c == 42 and d == "hot" merge into q;
halt 1; // terminates execution.
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