Energy prices as command prompt ASCII table -- Haskell version
The website jeroen.nl returns current and daily energy prices, but it would be nice to view this information from the command line. Haskell version.
Introduction
Earlier I created photonsphere.org/post/2025-03-15-command-line-energy-prices for this but when I moved from NixOS to Debian (stable), as described in photonsphere.org/post/2025-04-26-debian-declarative-install-script it no longer compiles.
Setbacks
My Elixir program to view energy prices from the command line does not compile -- presumably because Debian stable has an older BEAM version.
1$ make build
2mix escript.build
3
410:40:19.811 [error] Task #PID<0.211.0> started from #PID<0.96.0> terminating
5** (FunctionClauseError) no function clause matching in Hex.Solver.Constraint.Hex.Solver.Constraints.Empty.__impl__/1
6 (hex 2.1.1) Hex.Solver.Constraint.Hex.Solver.Constraints.Empty.__impl__(:target)
7 (elixir 1.14.0) lib/protocol.ex:672: Protocol.each_struct_clause_for/3
8 (elixir 1.14.0) lib/protocol.ex:650: anonymous fn/4 in Protocol.change_struct_impl_for/4
9 (elixir 1.14.0) lib/enum.ex:2468: Enum."-reduce/3-lists^foldl/2-0-"/3
10 (elixir 1.14.0) lib/protocol.ex:650: Protocol.change_struct_impl_for/4
11 (elixir 1.14.0) lib/protocol.ex:612: Protocol.change_debug_info/3
12 (elixir 1.14.0) lib/protocol.ex:563: Protocol.consolidate/2
13 (mix 1.14.0) lib/mix/tasks/compile.protocols.ex:140: Mix.Tasks.Compile.Protocols.consolidate/4
14Function: #Function<9.61781368/0 in Mix.Tasks.Compile.Protocols.consolidate/6>
15 Args: []
16** (EXIT from #PID<0.96.0>) an exception was raised:
17 ** (FunctionClauseError) no function clause matching in Hex.Solver.Constraint.Hex.Solver.Constraints.Empty.__impl__/1
18 (hex 2.1.1) Hex.Solver.Constraint.Hex.Solver.Constraints.Empty.__impl__(:target)
19 (elixir 1.14.0) lib/protocol.ex:672: Protocol.each_struct_clause_for/3
20 (elixir 1.14.0) lib/protocol.ex:650: anonymous fn/4 in Protocol.change_struct_impl_for/4
21 (elixir 1.14.0) lib/enum.ex:2468: Enum."-reduce/3-lists^foldl/2-0-"/3
22 (elixir 1.14.0) lib/protocol.ex:650: Protocol.change_struct_impl_for/4
23 (elixir 1.14.0) lib/protocol.ex:612: Protocol.change_debug_info/3
24 (elixir 1.14.0) lib/protocol.ex:563: Protocol.consolidate/2
25 (mix 1.14.0) lib/mix/tasks/compile.protocols.ex:140: Mix.Tasks.Compile.Protocols.consolidate/4
26
27make: *** [Makefile:29: build] Error 1
When confronted with a setback like this I tend to always look for the easiest solution. Hence I recoded the whole thing in Haskell ;-)
hdynprice
The Elixir program retrieves the content of the energy prices website and parses the data and displays an ASCII table and summary and is on CodeBerg: photonsphere/dynprice.
The Haskell version uses Megaparsec to parse HTML and JavaScript/JSON sections to retrieve the desired information. I could have used regular expressions like in the Elixir version, but, when confronted with a problem I tend to aways look for the easiest solution ;-) Plus parsers like these are well supported in Haskell. The software is on CodeBerg: photonsphere/hdynprice 1.
Usage
1$ hdynprice
2https://jeroen.nl/dynamische-energie/stroom/prijzen
3
4Tijd Totaal Inkoop per kWh
500:00 0.265 0.094
601:00 0.259 0.089
702:00 0.259 0.089
803:00 0.263 0.092
904:00 0.267 0.095
1005:00 0.269 0.097
1106:00 0.274 0.102
1207:00 0.269 0.097
1308:00 0.255 0.086
1409:00 0.168 0.014
1510:00 0.152 0.000
1611:00 0.151 -0.000
1712:00 0.150 -0.001
1813:00 0.148 -0.003
1914:00 0.148 -0.003
2015:00 0.151 -0.000
2116:00 0.151 0.000
2217:00 0.184 0.027
2318:00 0.224 0.060
2419:00 0.241 0.074
2520:00 0.256 0.086
2621:00 0.255 0.085
2722:00 0.264 0.093
2823:00 0.256 0.086
29
30Dynamische stroomprijzen voor vandaag
31De actuele dynamische inkoop prijs voor stroom is op dit moment 0.060100 euro per kWh (18:41).
32Hoogste prijs vandaag: 0.101640 euro per kWh (tussen 6:00 en 7:00).
33Laagste prijs vandaag: -0.003040 euro per kWh (tussen 13:00 en 14:00).
With the verbose option -- note the vertically printed read from bottom to top column names :)
1$ hdynprice --verbose
2https://jeroen.nl/dynamische-energie/stroom/prijzen
3
4 )
5 w
6 t
7 b
8
9 l
10 c
11 x
12 e
13 (
14
15 h
16 W
17 k
18
19 r
20 e
21 p
22
23 g )
24 n w
25 i t
26 d b
27 e
28 o l
29 g c
30 r x
31 e e
32 v (
33 p
34 o g )
35 o n %
36 h k i 1
37 W n t 2
38 k i s (
39 a
40 r e l W
41 e d e T
42 p l b B
43 e e
44 l p d i l
45 a o d g a
46d a o i r a
47j t k m e t
48i o n e n o
49T T I G E T
5000:00 0.265 0.094 0.024 0.102 0.046
5101:00 0.259 0.089 0.024 0.102 0.045
5202:00 0.259 0.089 0.024 0.102 0.045
5303:00 0.263 0.092 0.024 0.102 0.046
5404:00 0.267 0.095 0.024 0.102 0.046
5505:00 0.269 0.097 0.024 0.102 0.047
5606:00 0.274 0.102 0.024 0.102 0.048
5707:00 0.269 0.097 0.024 0.102 0.047
5808:00 0.255 0.086 0.024 0.102 0.044
5909:00 0.168 0.014 0.024 0.102 0.029
6010:00 0.152 0.000 0.024 0.102 0.026
6111:00 0.151 -0.000 0.024 0.102 0.026
6212:00 0.150 -0.001 0.024 0.102 0.026
6313:00 0.148 -0.003 0.024 0.102 0.026
6414:00 0.148 -0.003 0.024 0.102 0.026
6515:00 0.151 -0.000 0.024 0.102 0.026
6616:00 0.151 0.000 0.024 0.102 0.026
6717:00 0.184 0.027 0.024 0.102 0.032
6818:00 0.224 0.060 0.024 0.102 0.039
6919:00 0.241 0.074 0.024 0.102 0.042
7020:00 0.256 0.086 0.024 0.102 0.044
7121:00 0.255 0.085 0.024 0.102 0.044
7222:00 0.264 0.093 0.024 0.102 0.046
7323:00 0.256 0.086 0.024 0.102 0.044
74
75Dynamische stroomprijzen voor vandaag
76De actuele dynamische inkoop prijs voor stroom is op dit moment 0.060100 euro per kWh (18:42).
77Hoogste prijs vandaag: 0.101640 euro per kWh (tussen 6:00 en 7:00).
78Laagste prijs vandaag: -0.003040 euro per kWh (tussen 13:00 en 14:00).
-
Naming inspired by hledger -- https://hledger.org ↩︎