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EBNF grammar for SWMM input files
//
// swmm-input.lark
//
// Created: Dec 6, 2023
// Updated: Apr 20, 2024
//
// Author: Michael E. Tryby
// US EPA - ORD/CESER
//
// Notes: Use Earley parser
// Quote file paths
//
%import common.NEWLINE -> _NL
%import common.WS_INLINE -> _SP
%ignore _SP
%ignore _SP _NL
%ignore _COMMENT
%ignore _COMMENT _NL
start : _NL? section*
section : "[" KEYWORD "]" _EOR record*
record : field (_SP field)* _EOR
field : KEYWORD -> keyword
| EDGE_CASE -> keyword
| DATE -> date
| TIME -> time
| FLOAT -> float
| INTEGER -> integer
| OPERATOR -> operator
| PATH -> path
| NAME -> name
KEYWORD : /[\/#(A-Za-z)_-]+/
EDGE_CASE : /TYPE[1-5]|X1|PUMP[1-5]/
DATE : /\d{1,2}\/\d{1,2}(\/\d{4})?/
TIME : /\d{1,2}:\d{2}(:\d{2})?/
FLOAT : /(-)?(\d+\.\d*|\.\d+)/
OPERATOR : /=|<>|<=?|>=?/
PATH : /".*"/
NAME : /[^ \t\n\r\f\[\]";:]+/
INTEGER : /(?<!\.)\d+(?!\.\d)/
_COMMENT : /;[^\n]*/
_EOR : (_SP? (_NL | _COMMENT _NL))
#
# inputfile.py
#
# Created: Dec 7, 2023
# Updated: Jan 29, 2024
#
# Author: Michael E. Tryby
# US EPA - ORD/CESER
#
import sys
from lark import Lark, Visitor
NL = '\n'
SP = ' '
class TreeToInputFile(Visitor):
# Writes file parse tree to input file
def __init__(self):
self.buffer = []
def export(self):
print(''.join(self.buffer), end='')
def section(self, tree):
self.buffer.append(NL)
self.buffer.append(f"[{tree.children[0]}]" + NL)
def record(self, tree):
for sub_tree in tree.children:
self.buffer.append(sub_tree.children[0] + SP)
self.buffer.append(NL)
if __name__ == "__main__":
# Convert input file to parse tree
parser = Lark.open("swmm-input.lark")
with open(sys.argv[1]) as f:
file_tree = parser.parse(f.read())
print(file_tree.pretty())
# Convert parse tree to inputfile
tree_to_file = TreeToInputFile()
tree_to_file.visit_topdown(file_tree)
tree_to_file.export()

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12/11/2023: control and transect sections fixed

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12/14/2023: refactored keywords

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12/18/2023: added aliases for fields

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12/24/2023: added license

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michaeltryby commented Apr 15, 2024

04/15/2024: adds support for

  • signed floats
  • inline comments
  • file paths
  • element names
  • lowercase keywords

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michaeltryby commented Apr 16, 2024

04/16/2024: combines edge cases

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04/17/2024: adds support for

  • comment lines
  • comment records
  • comment fields

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michaeltryby commented Apr 19, 2024

04/19/2024:

  • ignore spaces
  • refactor

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04/20/2024:

  • ignore blank lines

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