oxigdal-algorithms 0.1.4

// Raster Algebra DSL Grammar for Pest Parser
//
// This grammar defines a complete DSL for raster algebra operations with:
// - Variables and assignments
// - Function definitions
// - Conditional expressions
// - Loops
// - Band references
// - Mathematical operations
// - Built-in functions

WHITESPACE = _{ " " | "\t" | "\r" | "\n" }
COMMENT = _{ "//" ~ (!"\n" ~ ANY)* ~ "\n" | "/*" ~ (!"*/" ~ ANY)* ~ "*/" }

// Identifiers and literals
ident = @{ ASCII_ALPHA ~ (ASCII_ALPHANUMERIC | "_")* }
number = @{ "-"? ~ ASCII_DIGIT+ ~ ("." ~ ASCII_DIGIT+)? ~ (^"e" ~ ("+" | "-")? ~ ASCII_DIGIT+)? }
band_ref = @{ ^"B" ~ ASCII_DIGIT+ }

// Keywords
let_kw = _{ ^"let" }
fn_kw = _{ ^"fn" }
if_kw = _{ ^"if" }
then_kw = _{ ^"then" }
else_kw = _{ ^"else" }
for_kw = _{ ^"for" }
in_kw = _{ ^"in" }
return_kw = _{ ^"return" }

// Operators
add_op = { "+" }
sub_op = { "-" }
mul_op = { "*" }
div_op = { "/" }
mod_op = { "%" }
pow_op = { "^" }

eq_op = { "==" }
ne_op = { "!=" }
le_op = { "<=" }
ge_op = { ">=" }
lt_op = { "<" }
gt_op = { ">" }

and_op = { "&&" | ^"and" }
or_op = { "||" | ^"or" }
not_op = { "!" | ^"not" }

// Program structure
program = { SOI ~ statement* ~ EOI }

statement = {
    variable_decl
  | function_decl
  | return_stmt
  | expr_stmt
}

variable_decl = { let_kw ~ ident ~ "=" ~ expression ~ ";" }

function_decl = {
    fn_kw ~ ident ~ "(" ~ param_list? ~ ")" ~ "=" ~ expression ~ ";"
}

param_list = { ident ~ ("," ~ ident)* }

return_stmt = { return_kw ~ expression ~ ";" }

expr_stmt = { expression ~ ";" }

// Expressions
expression = { logical_or }

logical_or = {
    logical_and ~ (or_op ~ logical_and)*
}

logical_and = {
    logical_not ~ (and_op ~ logical_not)*
}

logical_not = {
    not_op* ~ comparison
}

comparison = {
    additive ~ ((eq_op | ne_op | le_op | ge_op | lt_op | gt_op) ~ additive)?
}

additive = {
    multiplicative ~ ((add_op | sub_op) ~ multiplicative)*
}

multiplicative = {
    power ~ ((mul_op | div_op | mod_op) ~ power)*
}

power = {
    unary ~ (pow_op ~ unary)*
}

unary = {
    (sub_op | add_op) ~ unary
  | primary
}

primary = {
    number
  | band_ref
  | function_call
  | conditional
  | for_loop
  | variable_ref
  | block
  | "(" ~ expression ~ ")"
}

function_call = {
    ident ~ "(" ~ arg_list? ~ ")"
}

arg_list = {
    expression ~ ("," ~ expression)*
}

variable_ref = { ident }

conditional = {
    if_kw ~ expression ~ then_kw ~ expression ~ else_kw ~ expression
}

block = {
    "{" ~ statement* ~ expression? ~ "}"
}

// Range for loops
range = {
    expression ~ ".." ~ expression
}

for_loop = {
    for_kw ~ ident ~ in_kw ~ range ~ block
}