sas94

name	sas94
description	Use when user references a .sas file, SAS 9.4 code, DATA step constructs (MERGE/BY, first./last., retain, arrays, hash objects), PROC SQL, SAS macros (%macro, %sysfunc, quoting, symput/symget), base or stat procs (FREQ/MEANS/LOGISTIC/GLM/MIXED/GENMOD/SURVEY*/LIFETEST), ODS RTF/EXCEL/PDF, or PROC FORMAT. Not for R, Python, Stata, SPSS, generic SQL, Procfile, or git merges.
license	MIT
compatibility	Designed for Claude Code; does not execute SAS
allowed-tools	Read Grep Glob Write Edit
metadata	{"author":"Xiaosong Zhang","repository":"https://github.com/xiaosongz/sas94-skill","version":"0.1.0-beta.1"}

When to Use

Activate this skill when the user asks to:

• Write, review, or modify any .sas file
• Translate a study description into a SAS 9.4 program (DATA step, PROC SQL, macros)
• Debug a SAS program producing unexpected results, log errors, warnings, or NOTE-level diagnostics
• Build or repair a macro: %macro scope, %let, %sysfunc, quoting (%str, %nrstr, %bquote, %superq), &&var, call symput, symget()
• Author DATA step logic with MERGE/BY, first./last., retain, arrays, hash objects, PDV reasoning
• Write or audit PROC SQL (joins, dedup, INTO :macvar, RESET)
• Run base procs (FREQ, MEANS, UNIVARIATE, SORT, TRANSPOSE, REPORT, CONTENTS, DATASETS, IMPORT, EXPORT, COMPARE) or statistical procs (LOGISTIC, GLM, MIXED, GENMOD, SURVEY*, LIFETEST, PHREG)
• Capture proc output via ODS (RTF, EXCEL, PDF, ODS OUTPUT, ODS GRAPHICS, GTL)
• Build PROC FORMAT value/picture formats, or use date/time functions and input()/put() conversions
• Look up SAS function signatures (date arithmetic, string manipulation, numeric)

Prefer this skill whenever the current file or referenced path is a .sas file, or when the user references SAS 9.4 code (DATA step, PROC SQL, %macro, ODS, hash tables, etc.).

When NOT to Use

Skip even if keywords overlap — another skill or a generic response fits:

• R (dplyr, tidyverse, data.frame)
• Python (pandas, dataframe)
• Stata, SPSS
• Generic SQL (T-SQL, PostgreSQL, BigQuery)
• Procfile or shell "proc" commands
• Git merges — even when the user says "merge", "array", "dataframe", or "proc"

How to Use This Skill

References are organized as per-concept atoms under references/<topic>/<atom>.md, each ~100-200 lines, each carrying one to three Critical Rules plus CORRECT / WRONG code pairs. Load only the atom(s) your task actually needs. The Reference Routing table below is the authoritative map. Do not answer SAS questions from SKILL.md alone.

When the routing table is ambiguous, load the topic's _index.md first (cheap — 30-50 lines) and branch from there.

Base documentation URL (use when a reference atom is insufficient): documentation.sas.com/doc/en/pgmsascdc/9.4_3.5/ — browse or general web search.

STOP and Re-check — Known Silent-Failure Patterns

Stop and load the indicated atom before writing or reviewing code when you see any of these patterns. Each pattern is a documented SAS footgun that compiles or runs cleanly but produces wrong results or bypasses a guardrail.

• data a; set b; a = b + c; run; without retain — STOP. First row writes an uninitialized accumulator. Load references/data-step/retain-pdv.md.
• %macro foo; ... %mend; missing () in the macro signature — STOP. sasjs/lint hasMacroParentheses forbids this; silent-parameter bugs follow. Load references/macros/definition-syntax.md.
• proc sql; create table t as select * from a, b; (unqualified comma join) — STOP. This is a Cartesian product, not a join. Load references/proc-sql/joins.md.
• merge a b; by id; run; with shared payload column names — STOP. Right-table values silently overwrite left-table values on duplicate keys. Load references/data-step/merge.md.
• declare hash h(); h.definekey(...); h.definedata(...); h.definedone(); without length declared for key/data vars upstream — STOP. Hash vars inherit PDV length; undeclared → truncation. Load references/hash-tables/declare-and-length.md.
• %let x = &y; inside %macro without %local x; — STOP. Implicit outer-scope write when x exists at the caller's level. Load references/macros/scope-and-quoting.md.
• where derived_var = ...; after computing derived_var in the DATA step — STOP. WHERE is pre-PDV and cannot see derived columns. Load references/data-step/where-vs-if.md.
• proc datasets lib=<lib> kill; — STOP. Empties the library with no confirmation, no prompt. Load references/base-procs/schema-utils.md.
• proc import datafile='f.csv' out=ds; with no DBMS= / GUESSINGROWS=MAX — STOP. Default GUESSINGROWS=1 for CSV truncates row-1-short strings. Load references/base-procs/file-io.md.
• %put '&var'; expecting single quotes to suppress resolution — STOP. Macro processor tokenizes before the statement receives its argument. Load references/data-step/macro-quoting.md.

Reference Routing

Load the specific atom matching the trigger. Only load a topic's _index.md when the trigger is ambiguous across atoms within that topic.

Base SAS procedures

Trigger	Load
PROC FREQ, cross-tab, missing handling	references/base-procs/proc-freq.md
PROC MEANS, class-level summary, OUTPUT OUT=	references/base-procs/proc-means.md
PROC UNIVARIATE, quantiles	references/base-procs/proc-univariate.md
PROC SORT, NODUPKEY, NODUPRECS, OUT= overwrite	references/base-procs/proc-sort.md
PROC TRANSPOSE, long↔wide reshape	references/base-procs/proc-transpose.md
PROC REPORT, DEFINE, grouping	references/base-procs/proc-report.md
PROC PRINT, NOOBS, listing	references/base-procs/proc-print.md
PROC CONTENTS, PROC DATASETS, KILL, schema inspection	references/base-procs/schema-utils.md
PROC IMPORT, PROC EXPORT, DBMS=, GUESSINGROWS=, CSV / Excel IO	references/base-procs/file-io.md
PROC COMPARE, dataset equality, CRITERION=, METHOD=	references/base-procs/proc-compare.md

DATA step

Trigger	Load
MERGE, BY processing, same-name overwrite, coalesce	references/data-step/merge.md
LAG, queue semantics, conditional LAG	references/data-step/lag.md
PROC APPEND, BASE / DATA shape, FORCE	references/data-step/append.md
PROC SQL join vs DATA-step MERGE tradeoff	references/data-step/sql-vs-merge.md
retain, accumulator, PDV initialization	references/data-step/retain-pdv.md
WHERE vs subsetting IF, compile-time vs execute-time filter	references/data-step/where-vs-if.md
DATA-step single-quote vs double-quote string, %nrstr masking	references/data-step/macro-quoting.md
sasjs/lint file hygiene: indent, tabs, trailing space, gremlins, encoded passwords	references/data-step/file-hygiene.md

Macros

Trigger	Load
%macro / %mend signature, parens, nesting, Doxygen, required options	references/macros/definition-syntax.md
%local, %global, quoting (%str, %nrstr, %bquote, %superq), &&var, call symputx, symget	references/macros/scope-and-quoting.md
OPTIONS MPRINT / MLOGIC / SYMBOLGEN, OBS=0, %PUT _USER_ / _ALL_, macro debugging	references/macros/debugging.md
%INCLUDE vs %MACRO vs SET — file inclusion vs parameterized reuse	references/macros/include-vs-macro.md
%sysfunc, %eval, %sysevalf, macro arithmetic	references/macros/sysfunc-and-eval.md

Statistical procedures

Trigger	Load
PROC LOGISTIC, event='1', descending, CLASS reference coding	references/stat-procs/proc-logistic.md
PROC GLM, ANCOVA, LSMEANS, Type III SS	references/stat-procs/proc-glm.md
PROC MIXED, RANDOM vs REPEATED, SUBJECT=	references/stat-procs/proc-mixed.md
PROC GENMOD, DIST= / LINK=, GEE, offset	references/stat-procs/proc-genmod.md
PROC LIFETEST, Kaplan-Meier, TIME censor code	references/stat-procs/proc-lifetest.md
PROC PHREG, Cox PH, HAZARDRATIO	references/stat-procs/proc-phreg.md
PROC SURVEYMEANS / SURVEYFREQ / SURVEYLOGISTIC / SURVEYREG, design vars	references/stat-procs/proc-surveymeans.md

Hash tables

Trigger	Load
declare hash, definekey, definedata, definedone, PDV length match	references/hash-tables/declare-and-length.md
find(), check(), return-code guard, call missing() reset	references/hash-tables/find-check-rc.md
hiter, first(), next(), hash iteration, output()	references/hash-tables/iteration.md
multidata: 'Y', duplicate-key handling, default first-row-only trap	references/hash-tables/multidata.md
Dorfman streaming lookup, hash dedup, in-memory aggregator/counter	references/hash-tables/idioms.md

PROC SQL

Trigger	Load
Joins, COALESCE, qualified columns, Cartesian trap	references/proc-sql/joins.md
DISTINCT, GROUP BY, HAVING, dedup	references/proc-sql/dedup.md
INTO :mv, INTO :list, SEPARATED BY, dictionary tables	references/proc-sql/into-macvar.md
CASE WHEN (searched vs simple), ELSE	references/proc-sql/case-expressions.md
RESET, FEEDBACK, NOEXEC, CREATE TABLE AS	references/proc-sql/reset-and-options.md

ODS and output

Trigger	Load
ODS OUTPUT Table=ds;, ODS TRACE, capture proc output to dataset	references/ods-and-output/ods-output-capture.md
ODS RTF / ODS PDF / ODS EXCEL / ODS CSVALL, destinations, style=	references/ods-and-output/ods-destinations.md
ODS GRAPHICS, imagename=, GTL / proc template	references/ods-and-output/ods-graphics.md
ODS SELECT / ODS EXCLUDE, filter proc tables	references/ods-and-output/ods-select-exclude.md
ODS LISTING, text output, linesize / pagesize	references/ods-and-output/ods-listing.md

Formats and informats

Trigger	Load
put() vs input(), putn/inputn, trailing dot on reference	references/formats-informats/put-vs-input.md
PROC FORMAT, VALUE, INVALUE, PICTURE, CNTLIN=	references/formats-informats/proc-format.md
mmddyy10., yymmdd10., date9., datetime20., anydtdte., DATESTYLE=	references/formats-informats/date-formats.md
best., dollar., comma., w.d precision, truncation	references/formats-informats/numeric-formats.md

Functions

Trigger	Load
INTNX, INTCK, interval alignment, count-vs-duration trap	references/functions-dates/intnx-intck.md
MDY, YEAR, MONTH, DAY, WEEKDAY, TODAY	references/functions-dates/construction.md
DATEPART, TIMEPART, date vs datetime scale	references/functions-dates/datetime-parts.md
Date arithmetic, "add one month" via INTNX vs +30	references/functions-dates/date-arithmetic.md
CATS, CATX, CATT, CAT, || concatenation	references/functions-strings/concat.md
SCAN, SUBSTR, SUBSTRN, FIND, INDEX, COUNTW	references/functions-strings/parse.md
COMPRESS, TRANWRD, STRIP, TRIM, LEFT, COMPBL	references/functions-strings/clean.md
UPCASE, LOWCASE, PROPCASE, string comparison with blanks	references/functions-strings/case-and-compare.md
SUM(of ...), MEAN(of ...), row-wise aggregates, missing handling	references/functions-numeric/row-aggregates.md
ROUND, CEIL, FLOOR, MOD, ABS, precision	references/functions-numeric/arithmetic.md
DIM, HBOUND, LBOUND, array bounds	references/functions-numeric/arrays.md

Real-world idioms (fallback)

Trigger	Load
"how do SAS programmers do X", novel / unknown pattern	references/idioms-from-lexjansen/_index.md then branch
Dorfman hash techniques (streaming lookup, dedup, aggregator)	references/idioms-from-lexjansen/hash-idioms.md
Lafler CASE expressions, PROC SQL idioms	references/idioms-from-lexjansen/sql-idioms.md
Whitlock / Lepp macro quoting + dynamic code idioms	references/idioms-from-lexjansen/macro-idioms.md

Assets

Use these templates as starting points — they supply header comment blocks, not logic. Fill in body idioms by loading the relevant atom per the routing table above.

• assets/data-step-template.sas — generic DATA step skeleton
• assets/proc-sql-template.sas — PROC SQL skeleton
• assets/macro-template.sas — %macro / %mend skeleton with parenthesized signature
• assets/analysis-template.sas — end-to-end study-program scaffold

Workflow

1. Identify the trigger (file type, keyword, or explicit request) and match it to a row in the Reference Routing table.
2. Load the indicated atom — not SKILL.md — before writing or reviewing any non-trivial code.
3. Apply the STOP-and-Re-check patterns above as a pre-flight check for the most common silent-failure classes.
4. For new files, start from the matching assets/*.sas template.
5. When a pattern does not clearly match a single atom, load the topic's _index.md first (30-50 lines) then branch to the specific atom. For novel patterns, start with references/idioms-from-lexjansen/_index.md.
6. If an atom is insufficient, fall back to the SAS documentation base URL above.

Shell commands. Skill does not execute SAS. Atoms suggest diagnostic shell commands (hexdump, file) for inspecting .sas bytes — Bash not pre-approved, prompts at project scope.