sep

Name: sep
Author: managedcode

461stars35forks

How to install sep?

managedcode/dotnet-skills/sep

$npx -y skills add managedcode/dotnet-skills --skill sep

Installs into the current project.

Summary

Use Sep for high-performance separated-value parsing and writing in .NET, including delimiter inference, explicit parser/writer options, and low-allocation row/column workflows. USE FOR: delimited data needs are performance-sensitive and allocation-aware; project needs explicit c

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SKILL.md

1	# Sep for .NET separated values
2
3	## Trigger On
4
5	- delimited data needs are performance-sensitive and allocation-aware
6	- project needs explicit control over separator inference, escaping, trimming, and header behavior
7	- reading/writing large or long-lived file pipelines in ML, ETL, or analytics workloads
8	- startup/perf tests require AOT/trimming-friendly CSV/TSV processing
9
10	## Install
11
12	- NuGet:
13	- `dotnet add package Sep`
14	- `dotnet add package Sep --version <version>`
15	- XML package reference:
16	- `<PackageReference Include="Sep" Version="x.y.z" />`
17	- Verify baseline support by checking the package page:
18	- [NuGet: Sep](https://www.nuget.org/packages/Sep/)
19	- Source:
20	- [GitHub: nietras/Sep](https://github.com/nietras/Sep)
21
22	## Workflow
23
24	```mermaid
25	flowchart LR
26	A[Input source: file/text/stream] --> B[Sep.Reader or Sep.New(...).Reader]
27	B --> C[SepReaderOptions]
28	C --> D[Rows -> Cols -> Span/Parse]
29	D --> E[Transform and validate]
30	E --> F[SepWriter via SepWriterOptions]
31	F --> G[To file/text output]
32	```
33
34	1. Decide schema shape
35	- header present or no header
36	- separator known (`;`, `,`, tab, custom) or infer from first row
37	- row/column quoting rules
38	2. Build reader with `Sep.Reader(...)` and explicit options only where needed:
39	- `Sep.Reader()` for inferred separator from header-like first row
40	- `Sep.New(',').Reader(...)` for explicit separator mode
41	- `Sep.Reader(o => o with { HasHeader = false })` if header is absent
42	3. Read rows and map columns as `ReadOnlySpan<char>` first, convert only when needed.
43	4. For output, use `reader.Spec.Writer()` when you need the same separator/culture as input.
44	5. Control writer behavior with `Sep.Writer(...)` and `SepWriterOptions` (`WriteHeader`, `Escape`, `DisableColCountCheck`).
45	6. Add async only where it brings value and your runtime is C# 13 / .NET 9+ for `await foreach` over async reader rows.
46	7. Use `ParallelEnumerate` for CPU-heavy transformations only after benchmarking single-threaded baseline.
47
48	### Install and read patterns
49
50	```csharp
51	using var reader = Sep.Reader(o => o with
52	{
53	HasHeader = true,
54	Unescape = true,
55	Trim = SepTrim.Both
56	}).FromText(data);
57
58	foreach (var row in reader)
59	{
60	var id = row["Id"].Parse<int>();
61	var name = row[1].ToString();
62	// process row
63	}
64	```
65
66	### Write patterns
67
68	```csharp
69	using var reader = Sep.Reader().FromFile("input.csv");
70	using var writer = reader.Spec.Writer().ToFile("output.csv");
71
72	foreach (var row in reader)
73	{
74	using var writeRow = writer.NewRow(row);
75	writeRow["Amount"].Format(row["Amount"].Parse<double>() * 1.2);
76	}
77	```
78
79	### Async reading and writing
80
81	```csharp
82	var text = "A;B\n1;hello\n";
83
84	using var reader = await Sep.Reader().FromTextAsync(text);
85	await using var writer = reader.Spec.Writer().ToText();
86
87	await foreach (var row in reader)
88	{
89	await using var writeRow = writer.NewRow(row);
90	var normalized = row["B"].ToString().ToUpperInvariant();
91	writeRow["B"].Set(normalized);
92	}
93	```
94
95	### Common configuration patterns
96
97	- Header-driven read
98	- default `HasHeader = true`
99	- query by name: `row["ColName"]`
100	- Headerless pipelines
101	- `HasHeader = false`
102	- use index-based access: `row[0]`, `row[1]`
103	- Round-trip output
104	- start writer with `reader.Spec.Writer()` to preserve inference and formatting contract
105	- Speed-first processing
106	- keep default buffer + culture unless profiling proves a need to tune
107
108	## Best practices
109
110	- Parse to primitive types with `Parse<T>` in hot paths to avoid extra allocations.
111	- Keep `ToString`/format conversions at the edge (presentational layers), not in inner loops.
112	- Prefer `Unescape`, `Trim`, and `DisableQuotesParsing` settings deliberately and test with realistic samples.
113	- For large transforms, isolate heavy CPU work after enumeration and then apply `ParallelEnumerate` where appropriate.
114
115	## Limitations to check before production
116
117	- `SepReader.Row` and `SepWriter.Row` are `ref struct`s:
118	- avoid patterns that store rows beyond immediate scope
119	- materialize if you truly need random async/LINQ-style buffering
120	- `SepReader` row iteration is row-by-row by design; it is intentionally not the same as a classic collection model.
121
122	## Deliver
123
124	- installation and usage guide that is ready to c

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sep

461stars35forks

View on GitHub

How to install sep?

managedcode/dotnet-skills/sep

$npx -y skills add managedcode/dotnet-skills --skill sep

Installs into the current project.

Summary

Files · 1

View on GitHub

SKILL.md

1	# Sep for .NET separated values
2
3	## Trigger On
4
5	- delimited data needs are performance-sensitive and allocation-aware
6	- project needs explicit control over separator inference, escaping, trimming, and header behavior
7	- reading/writing large or long-lived file pipelines in ML, ETL, or analytics workloads
8	- startup/perf tests require AOT/trimming-friendly CSV/TSV processing
9
10	## Install
11
12	- NuGet:
13	- `dotnet add package Sep`
14	- `dotnet add package Sep --version <version>`
15	- XML package reference:
16	- `<PackageReference Include="Sep" Version="x.y.z" />`
17	- Verify baseline support by checking the package page:
18	- [NuGet: Sep](https://www.nuget.org/packages/Sep/)
19	- Source:
20	- [GitHub: nietras/Sep](https://github.com/nietras/Sep)
21
22	## Workflow
23
24	```mermaid
25	flowchart LR
26	A[Input source: file/text/stream] --> B[Sep.Reader or Sep.New(...).Reader]
27	B --> C[SepReaderOptions]
28	C --> D[Rows -> Cols -> Span/Parse]
29	D --> E[Transform and validate]
30	E --> F[SepWriter via SepWriterOptions]
31	F --> G[To file/text output]
32	```
33
34	1. Decide schema shape
35	- header present or no header
36	- separator known (`;`, `,`, tab, custom) or infer from first row
37	- row/column quoting rules
38	2. Build reader with `Sep.Reader(...)` and explicit options only where needed:
39	- `Sep.Reader()` for inferred separator from header-like first row
40	- `Sep.New(',').Reader(...)` for explicit separator mode
41	- `Sep.Reader(o => o with { HasHeader = false })` if header is absent
42	3. Read rows and map columns as `ReadOnlySpan<char>` first, convert only when needed.
43	4. For output, use `reader.Spec.Writer()` when you need the same separator/culture as input.
44	5. Control writer behavior with `Sep.Writer(...)` and `SepWriterOptions` (`WriteHeader`, `Escape`, `DisableColCountCheck`).
45	6. Add async only where it brings value and your runtime is C# 13 / .NET 9+ for `await foreach` over async reader rows.
46	7. Use `ParallelEnumerate` for CPU-heavy transformations only after benchmarking single-threaded baseline.
47
48	### Install and read patterns
49
50	```csharp
51	using var reader = Sep.Reader(o => o with
52	{
53	HasHeader = true,
54	Unescape = true,
55	Trim = SepTrim.Both
56	}).FromText(data);
57
58	foreach (var row in reader)
59	{
60	var id = row["Id"].Parse<int>();
61	var name = row[1].ToString();
62	// process row
63	}
64	```
65
66	### Write patterns
67
68	```csharp
69	using var reader = Sep.Reader().FromFile("input.csv");
70	using var writer = reader.Spec.Writer().ToFile("output.csv");
71
72	foreach (var row in reader)
73	{
74	using var writeRow = writer.NewRow(row);
75	writeRow["Amount"].Format(row["Amount"].Parse<double>() * 1.2);
76	}
77	```
78
79	### Async reading and writing
80
81	```csharp
82	var text = "A;B\n1;hello\n";
83
84	using var reader = await Sep.Reader().FromTextAsync(text);
85	await using var writer = reader.Spec.Writer().ToText();
86
87	await foreach (var row in reader)
88	{
89	await using var writeRow = writer.NewRow(row);
90	var normalized = row["B"].ToString().ToUpperInvariant();
91	writeRow["B"].Set(normalized);
92	}
93	```
94
95	### Common configuration patterns
96
97	- Header-driven read
98	- default `HasHeader = true`
99	- query by name: `row["ColName"]`
100	- Headerless pipelines
101	- `HasHeader = false`
102	- use index-based access: `row[0]`, `row[1]`
103	- Round-trip output
104	- start writer with `reader.Spec.Writer()` to preserve inference and formatting contract
105	- Speed-first processing
106	- keep default buffer + culture unless profiling proves a need to tune
107
108	## Best practices
109
110	- Parse to primitive types with `Parse<T>` in hot paths to avoid extra allocations.
111	- Keep `ToString`/format conversions at the edge (presentational layers), not in inner loops.
112	- Prefer `Unescape`, `Trim`, and `DisableQuotesParsing` settings deliberately and test with realistic samples.
113	- For large transforms, isolate heavy CPU work after enumeration and then apply `ParallelEnumerate` where appropriate.
114
115	## Limitations to check before production
116
117	- `SepReader.Row` and `SepWriter.Row` are `ref struct`s:
118	- avoid patterns that store rows beyond immediate scope
119	- materialize if you truly need random async/LINQ-style buffering
120	- `SepReader` row iteration is row-by-row by design; it is intentionally not the same as a classic collection model.
121
122	## Deliver
123
124	- installation and usage guide that is ready to c

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